JP2009256790A - Coating method of titanium oxide - Google Patents
Coating method of titanium oxide Download PDFInfo
- Publication number
- JP2009256790A JP2009256790A JP2009069155A JP2009069155A JP2009256790A JP 2009256790 A JP2009256790 A JP 2009256790A JP 2009069155 A JP2009069155 A JP 2009069155A JP 2009069155 A JP2009069155 A JP 2009069155A JP 2009256790 A JP2009256790 A JP 2009256790A
- Authority
- JP
- Japan
- Prior art keywords
- titanium oxide
- voltage
- particles
- film
- electrodeposition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 88
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 title claims abstract description 86
- 238000000576 coating method Methods 0.000 title abstract description 17
- 239000002245 particle Substances 0.000 claims abstract description 96
- 238000000034 method Methods 0.000 claims abstract description 42
- 238000004070 electrodeposition Methods 0.000 claims abstract description 40
- 239000003792 electrolyte Substances 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- 239000002612 dispersion medium Substances 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 10
- 239000005486 organic electrolyte Substances 0.000 claims abstract description 7
- 238000005245 sintering Methods 0.000 claims description 6
- 230000001699 photocatalysis Effects 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 abstract description 12
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 abstract description 9
- 239000002270 dispersing agent Substances 0.000 abstract description 9
- 229920000642 polymer Polymers 0.000 abstract description 8
- 239000006185 dispersion Substances 0.000 abstract description 7
- 239000011941 photocatalyst Substances 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 4
- 238000013508 migration Methods 0.000 abstract description 4
- 230000005012 migration Effects 0.000 abstract description 4
- 239000010408 film Substances 0.000 description 54
- 239000000758 substrate Substances 0.000 description 19
- 238000001962 electrophoresis Methods 0.000 description 18
- 238000009826 distribution Methods 0.000 description 15
- 239000000843 powder Substances 0.000 description 13
- 229910010413 TiO 2 Inorganic materials 0.000 description 12
- 239000000725 suspension Substances 0.000 description 11
- 238000001652 electrophoretic deposition Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 238000002474 experimental method Methods 0.000 description 9
- 239000010936 titanium Substances 0.000 description 9
- 239000007864 aqueous solution Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000002105 nanoparticle Substances 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000011550 stock solution Substances 0.000 description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 239000010935 stainless steel Substances 0.000 description 5
- 229910052719 titanium Inorganic materials 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- 238000004220 aggregation Methods 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000004062 sedimentation Methods 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 229910002012 Aerosil® Inorganic materials 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002296 dynamic light scattering Methods 0.000 description 3
- 230000005684 electric field Effects 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011255 nonaqueous electrolyte Substances 0.000 description 2
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 238000000634 powder X-ray diffraction Methods 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000000790 scattering method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000009210 therapy by ultrasound Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910021642 ultra pure water Inorganic materials 0.000 description 2
- 239000012498 ultrapure water Substances 0.000 description 2
- 230000005653 Brownian motion process Effects 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 238000005537 brownian motion Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000009501 film coating Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
Abstract
Description
本発明は、酸化チタンをコーティングする方法に関し、より詳しくは、泳動電着を利用した方法に関する。また、このように酸化チタンがコーティングされた光触媒材料、及びその製造方法に関する。 The present invention relates to a method for coating titanium oxide, and more particularly to a method using electrophoretic electrodeposition. The present invention also relates to a photocatalytic material coated with titanium oxide and a method for producing the same.
光触媒としてその機能が期待されている酸化チタンは、水、溶剤、バインダー、ｐＨ調整剤等と混ぜた組成物として基材表面に塗布されることが一般に知られている。しかしながら、このように塗布された酸化チタンは、仮に焼成工程を経ても必ずしも密着強度が十分であると言えない。また、含まれるバインダー等により酸化チタンが被覆され、光触媒機能が十分に発揮できないおそれもある。 It is generally known that titanium oxide, which is expected to function as a photocatalyst, is applied to the surface of a substrate as a composition mixed with water, a solvent, a binder, a pH adjuster and the like. However, it can not be said that the titanium oxide coated in this way has sufficient adhesion strength even if it undergoes a firing step. Moreover, there is a possibility that titanium oxide is coated with the contained binder and the like, and the photocatalytic function cannot be sufficiently exhibited.
ところで、酸化物粉末を導電性基材へコーティングする手法の一つに電気泳動電着がある。例えば、酸化物粉末が分散したサスペンション中に電極としての導電性基材を配置し、電位をかけ、酸化物粉末を電気泳動させてこの導電性基材上に堆積する。この技術は、大面積にコーティングすることが可能であり、コーティング膜厚の制御が容易であり、更に比較的低コストであるという特徴を持つ。しかしながら、この方法で金属基材に酸化チタンをコーティングしようとしても、コーティング速度が遅く実用に耐えず、コーティング膜の密着性も必ずしも十分とは言えない。そのため、後に行う焼成工程において、コーティング膜の剥離が生じやすい。 Incidentally, electrophoretic electrodeposition is one of the techniques for coating an oxide powder on a conductive substrate. For example, a conductive base material as an electrode is placed in a suspension in which oxide powder is dispersed, an electric potential is applied, and the oxide powder is electrophoresed and deposited on the conductive base material. This technique has the characteristics that it is possible to coat a large area, the control of the coating film thickness is easy, and the cost is relatively low. However, even if an attempt is made to coat titanium oxide on a metal substrate by this method, the coating speed is slow and cannot be practically used, and the adhesion of the coating film is not necessarily sufficient. Therefore, the coating film is likely to be peeled off in the subsequent baking step.
更に、紫外線照射を行った酸化チタン−ＩＰＡ系サスペンションを用いて、金属をはじめとする導電性の基材に電気泳動電着を行うことにより、カソード電極において、酸化チタン成膜とＩＰＡ由来のガス発生を同時に生じさせることで、コーティング膜表面に光触媒として好適な粗さを備えた酸化チタン薄膜を作製することが開示されている（例えば、特許文献１）。しかし、この方法では多孔質の膜ができてしまうので、膜の部分欠損等、膜質の低下が懸念される。 Further, by performing electrophoretic electrodeposition on a conductive substrate such as metal using a titanium oxide-IPA suspension subjected to ultraviolet irradiation, a titanium oxide film and an IPA-derived gas are formed on the cathode electrode. It has been disclosed that a titanium oxide thin film having a roughness suitable as a photocatalyst on the surface of a coating film is produced by causing the generation simultaneously (for example, Patent Document 1). However, since this method produces a porous film, there is a concern about deterioration of the film quality such as partial film loss.
一方、金属析出物中にナノ粒子を含む複合コーティングの電着において、パルス電圧をかけることにより、金属コーティング中により高濃度のナノ粒子を含ませることができる技術が開示されている（例えば、非特許文献１）。しかしながら、金属コーティングをすることが前提のコーティング方法では、光触媒としての活性を有する酸化チタンをできるだけ多く基材表面に付着させることができない。 On the other hand, in the electrodeposition of a composite coating containing nanoparticles in a metal deposit, a technique has been disclosed that allows a higher concentration of nanoparticles to be included in the metal coating by applying a pulse voltage (for example, non-deposition). Patent Document 1). However, the coating method premised on metal coating cannot attach as much titanium oxide having photocatalytic activity as possible to the substrate surface.
このように、光触媒としての活性を有する酸化チタンを含む被膜であって、十分な膜質を有するものを密着性よく、導電性の基材表面に付着させることを目的とする。 As described above, an object of the present invention is to attach a film containing titanium oxide having activity as a photocatalyst and having sufficient film quality to the surface of a conductive substrate with good adhesion.
酸化チタン粒子を含む分散媒中に、変動する電圧を用いて行う泳動電着により酸化チタン膜を製造する方法を提供することができる。 A method for producing a titanium oxide film by electrophoretic electrodeposition using a varying voltage in a dispersion medium containing titanium oxide particles can be provided.
より具体的には、以下のようなものを提供する。
（１）酸化チタン粒子を含む分散媒中にパルス状の電圧を用いて行う泳動電着により酸化チタン膜を製造する方法を提供することができる。
More specifically, the following is provided.
(1) A method for producing a titanium oxide film by electrophoretic electrodeposition using a pulsed voltage in a dispersion medium containing titanium oxide particles can be provided.
ここで、酸化チタン粒子は、一次径として、光触媒としての活性度を考慮すれば、平均粒径が、５０ｎｍ以下が好ましく、３０ｎｍ以下がより好ましく、１０ｎｍ以下がさらに好ましい。また、取り扱いの容易さ、保存性等を考慮すれば、この平均粒径が、１ｎｍ以上が好ましく、１０ｎｍ以上がより好ましく、３０ｎｍ以上がさらに好ましい。なお、平均粒径は、例えば以下のように定義することができる。粒子径は、沈降法による測定においては沈降速度が等価な球の直径として、レーザ散乱法においては散乱特性が等価な球の直径として定義できる。また、粒子径の分布を粒度（粒径）分布という。粒径分布において、ある粒子径より大きい質量の総和が、全粉体のそれの５０％を占める場合の粒子径が、平均粒径Ｄ５０として定義される。この定義および用語は、いずれも当業者において周知であり、例えば、ＪＩＳＺ８９０１「試験用粉体及び試験用粒子」、または、粉体工学会編「粉体の基礎物性」（ＩＳＢＮ４−５２６−０５５４４−１）の第１章等諸文献に記載されている。そして、レーザ散乱式の測定装置を使用して、粒子径に対する体積換算の積算頻度分布を測定することができるが、密度がほぼ一定であるので、体積換算と重量換算の分布は等しい。この積算（累積）頻度分布における５０％に相当する粒子径を求めて、平均粒径Ｄ５０とすることができる。ここでは平均粒径は、上述のレーザ散乱法による粒度分布測定手段によって測定する粒度分布の中央価（Ｄ５０）に基づく。平均粒径を求める手段については、上述以外にも多様な手段が開発され、現在も続いている現状にあり、測定値に若干の違いが生じることもあり得るが、平均粒径それ自体の意味、意義は明確であり、必ずしも上記手段に限定されない。また、パルス状の電圧とは、変動する電圧を意味してよい。例えば、電圧が最小電圧（０Ｖ）と最大電圧（６０Ｖ）の間を矩形波で変動するものを含んでよく、なだらかな波形で変形するものを含むこともできる。最小電圧と最大電圧の差は、１０Ｖ以上が好ましい。或いは、共に２乗した２乗最小電圧と２乗最大電圧の比が、３６０以下であることが好ましい。電圧は、正の方向にのみ（若しくは負の方向にのみ）変動してもよく、正負に跨って変動してもよい。 Here, considering the activity as a photocatalyst as the primary diameter, the titanium oxide particles preferably have an average particle diameter of 50 nm or less, more preferably 30 nm or less, and even more preferably 10 nm or less. In view of ease of handling, storage stability, and the like, the average particle diameter is preferably 1 nm or more, more preferably 10 nm or more, and further preferably 30 nm or more. The average particle diameter can be defined as follows, for example. The particle diameter can be defined as the diameter of a sphere with an equivalent sedimentation velocity in the measurement by the sedimentation method, and as the diameter of a sphere with an equivalent scattering property in the laser scattering method. The particle size distribution is referred to as particle size (particle size) distribution. In the particle size distribution, the particle size when the sum of masses larger than a certain particle size occupies 50% of the total powder is defined as the average particle size D50. These definitions and terms are both well known to those skilled in the art. For example, JISZ8901 “Test Powder and Test Particles” or “Basic Properties of Powder” (ISBN4-526-05544) edited by the Society of Powder Technology It is described in documents such as Chapter 1 of 1). Then, the integrated frequency distribution in terms of volume with respect to the particle diameter can be measured using a laser scattering type measuring device, but since the density is substantially constant, the volume conversion and the weight conversion distribution are the same. The particle diameter corresponding to 50% in this integrated (cumulative) frequency distribution can be obtained and used as the average particle diameter D50. Here, the average particle size is based on the median value (D50) of the particle size distribution measured by the particle size distribution measuring means by the laser scattering method described above. Various means other than those described above have been developed to determine the average particle diameter, and there are still some differences in the measured values. The significance is clear and is not necessarily limited to the above means. Further, the pulse voltage may mean a fluctuating voltage. For example, the voltage may include a voltage that fluctuates between a minimum voltage (0 V) and a maximum voltage (60 V) with a rectangular wave, and may include a voltage that deforms with a gentle waveform. The difference between the minimum voltage and the maximum voltage is preferably 10 V or more. Alternatively, it is preferable that the ratio of the squared minimum voltage and the squared maximum voltage squared together is 360 or less. The voltage may vary only in the positive direction (or only in the negative direction) or may vary across the positive and negative.
（２）前記パルス状の電圧は、その周波数が１Ｈｚ〜１００Ｈｚである上記（１）に記載の酸化チタン膜を製造する方法を提供することができる。 (2) The pulsed voltage can provide a method for producing the titanium oxide film according to (1), wherein the frequency is 1 Hz to 100 Hz.
パルス状の電圧は、周期的に変動することが好ましい。その周期は、１Ｈｚ以上が好ましく、１０Ｈｚ以上がより好ましく、３０Ｈｚ以上が更に好ましい。また、同周期は、１００Ｈｚ以下が好ましく、８０Ｈｚ以下がより好ましく、７０Ｈｚ以下が更に好ましい。 The pulse voltage preferably varies periodically. The period is preferably 1 Hz or more, more preferably 10 Hz or more, and further preferably 30 Hz or more. The same period is preferably 100 Hz or less, more preferably 80 Hz or less, and still more preferably 70 Hz or less.
（３）前記分散媒が水系電解質であることを特徴とする上記（１）又は（２）に記載の酸化チタン膜を製造する方法を提供することができる。 (3) The method for producing a titanium oxide film according to (1) or (2) above, wherein the dispersion medium is an aqueous electrolyte.
ここで、上記水系電解質は、水系溶剤中に平均一次粒径５〜５０ｎｍ及び平均分散粒径１０〜１００ｎｍの酸化チタン分散粒子（例えば、日本アエロジル製Ｐ２５等）と、立体反発を利用するタイプの高分子分散剤（例えば、酸基を有する共重合物のアルキロールアミン塩からなる分散剤、又は、顔料に親和性のある基を有する高分子量ブロック共重合物の水溶液、等）と、を含み、ｐＨ値がｐＨ５〜９の範囲内であってもよい。また、更に、アルコキシシラン加水分解重縮合物と、有機アミン類とを含んでもよい。 Here, the aqueous electrolyte is a titanium oxide dispersed particle having an average primary particle diameter of 5 to 50 nm and an average dispersed particle diameter of 10 to 100 nm in an aqueous solvent (for example, P25 manufactured by Nippon Aerosil Co., Ltd.) and a type utilizing steric repulsion. A polymer dispersant (for example, a dispersant composed of an alkylolamine salt of a copolymer having an acid group, or an aqueous solution of a high molecular weight block copolymer having a group having an affinity for a pigment). The pH value may be in the range of pH 5-9. Furthermore, you may contain an alkoxysilane hydrolysis polycondensate and organic amines.
そして、本発明の均一分散性光触媒コーティング液を製造する際に用いる酸化チタン分散水溶液は、酸化チタン粉体と高分子分散剤とを原料として調製される。ここで、酸化チタン粉体としては、好ましくは、例えば日本アエロジル製P25を用いることができ、また、高分子分散剤としては、好ましくは立体反発を利用するタイプの高分子分散剤（例えば、ビックケミー・ジャパン社販売の商品名Ｄｉｓｐｅｒｂｙｋ−１８０、Ｄｉｓｐｅｒｂｙｋ−１９０等）を用いることができる。そして、この高分子分散剤の使用量は、酸化チタン粉体の重量に対して１０重量％以上１００重量％以下であるのがよく、好ましくは３０重量％以上６０重量％以下の範囲であるのがよい。そして、この酸化チタン分散水溶液は、分散機、好ましくはビーズミル分散機を使用して分散安定化することにより調製される。 And the titanium oxide dispersion aqueous solution used when manufacturing the uniformly dispersible photocatalyst coating liquid of this invention is prepared by using a titanium oxide powder and a polymer dispersant as raw materials. Here, as the titanium oxide powder, for example, P25 manufactured by Nippon Aerosil Co., Ltd. can be preferably used, and as the polymer dispersant, preferably a polymer dispersant of a type utilizing steric repulsion (for example, Big Chemie). -Trade names such as Disperbyk-180 and Disperbyk-190 sold by Japan, Inc.) can be used. The amount of the polymer dispersant used is preferably 10% by weight or more and 100% by weight or less, and preferably 30% by weight or more and 60% by weight or less based on the weight of the titanium oxide powder. Is good. And this titanium oxide dispersion aqueous solution is prepared by carrying out dispersion stabilization using a disperser, preferably a bead mill disperser.
また、平均一次粒径２１nmの酸化チタン粉体（日本アエロジルＰ２５）と立体反発を利用するタイプの高分子分散剤（ビックケミー・ジャパン社販売の商品名：Ｄｉｓｐｅｒｂｙｋ−１８０）を水に添加して、分散機としてビーズミル分散機を用いて、粒子濃度３０重量％の平均分散粒径８０ｎｍの酸化チタン粒子分散水溶液を調製して、水系電解質としてもよい。この場合好ましくは、カチオンとしてカリウムイオンを含むことができる。上記調製された水溶液は、常温で１年以上経過しても酸化チタン粒子が沈降せずに分散安定化する。また、液中の平均分散粒径は光散乱式粒度分布計を用いて測定できる。 Further, a titanium oxide powder having an average primary particle size of 21 nm (Nippon Aerosil P25) and a polymer dispersant of a type utilizing steric repulsion (trade name: Disperbyk-180 sold by Big Chemie Japan) are added to water, A bead mill disperser may be used as a disperser to prepare a titanium oxide particle-dispersed aqueous solution having an average dispersed particle size of 80 nm with a particle concentration of 30% by weight, and the aqueous electrolyte may be used. In this case, potassium ions can be preferably contained as cations. The aqueous solution prepared above is dispersed and stabilized without settling of titanium oxide particles even after one year or more at room temperature. The average dispersed particle size in the liquid can be measured using a light scattering particle size distribution meter.
（４）前記分散媒が有機系電解質であることを特徴とする上記（１）又は（２）に記載の酸化チタン膜を製造する方法を提供することができる。 (4) The method for producing a titanium oxide film according to (1) or (2) above, wherein the dispersion medium is an organic electrolyte.
（５）更に、電着された膜を焼結する工程を更に含むことを特徴とする上記（１）から（４）のいずれかに記載の酸化チタン膜を製造する方法を提供することができる。 (5) The method for producing a titanium oxide film according to any one of (1) to (4), further comprising a step of sintering the electrodeposited film can be provided. .
（６）上記（１）から（５）のいずれかの方法により製造された酸化チタン膜を提供することができる。 (6) A titanium oxide film manufactured by any one of the methods (1) to (5) can be provided.
（７）上記（６）の酸化チタン膜を含む光触媒材料を提供することができる。 (7) A photocatalytic material including the titanium oxide film of (6) can be provided.
ここで、酸化チタン膜を構成する酸化チタン粒子について、その沈降特性や泳動特性について考察する。溶媒中の酸化チタン粒子には、鉛直方向に重力及び浮力が作用し、水平方向に電気泳動を生じさせる電場による力が作用すると仮定する。鉛直方向及び水平方向の力は、それぞれ直交するため、独立して考えることができる。このとき、電極間を水平に所定の沈降深さ以下で移動できた場合、その酸化チタン粒子は、電極に付着して膜を構成すると仮定することができる。酸化チタン粒子の密度はほぼ一定であるので、鉛直方向の重力及び浮力（相殺して沈降力）は体積（球近似された場合、半径の３乗）に比例する。沈降速度は、酸化チタン粒子抵抗断面積（球近似された場合、半径の２乗）に比例する抵抗力と沈降力が釣り合い一定であるとすることができるので、半径に比例して大きくなると考えることができる。従って、所定の沈降深さに至るまでの時間は、半径に反比例すると考えられ、より小さい酸化チタン粒子が電極に付着しやすいことがわかる。また、酸化チタン粒子の電荷が一定であるとすれば、水平方向の力は電場の変化と同様に変化する。このとき大きい酸化チタン粒子はブラウン運動のような動きをする溶媒分子からの力を受け易くなるだけでなく、慣性が大きいのでこの電場の変化に応じて直ぐに加速され難い。一方、小さい酸化チタン粒子は直ぐに加速されて陰極方向に進み出し易い。このため、パルス状の電圧をかけると小さい酸化チタン粒子の方が短時間に相手電極に到達し易いと考えられる。以上より、所定の沈降深さ以下で相手電極に到達するのは、より細かい酸化チタン粒子であることが分かる。そして、より細かい酸化チタン粒子は、光触媒としての機能がより高いと考えられ、これらを多く集めた酸化チタン膜は、より好ましい膜であるということもできると考えられる。 Here, the sedimentation characteristics and migration characteristics of the titanium oxide particles constituting the titanium oxide film will be considered. It is assumed that gravity and buoyancy act on the titanium oxide particles in the solvent in the vertical direction, and force due to an electric field that causes electrophoresis in the horizontal direction. Since the forces in the vertical direction and the horizontal direction are orthogonal to each other, they can be considered independently. At this time, if it is possible to move horizontally between the electrodes at a predetermined settling depth or less, it can be assumed that the titanium oxide particles adhere to the electrodes to form a film. Since the density of the titanium oxide particles is almost constant, gravity and buoyancy in the vertical direction (cancelling and settling force) are proportional to the volume (the cube of the radius when approximated to a sphere). The settling velocity can be considered to increase in proportion to the radius because the resistance force and the settling force proportional to the titanium oxide particle resistance cross-sectional area (the square of the radius when approximated to a sphere) can be assumed to be constant. be able to. Therefore, it can be considered that the time to reach a predetermined settling depth is inversely proportional to the radius, and smaller titanium oxide particles tend to adhere to the electrode. If the charge of the titanium oxide particles is constant, the horizontal force changes in the same manner as the electric field changes. At this time, the large titanium oxide particles are not only easily subjected to the force from the solvent molecules moving like the Brownian motion, but also have a large inertia, so that they are not easily accelerated according to the change in the electric field. On the other hand, small titanium oxide particles are readily accelerated and tend to proceed toward the cathode. For this reason, when a pulse voltage is applied, it is considered that small titanium oxide particles can easily reach the counterpart electrode in a short time. From the above, it can be seen that it is finer titanium oxide particles that reach the counterpart electrode at a predetermined sedimentation depth or less. Further, finer titanium oxide particles are considered to have a higher function as a photocatalyst, and a titanium oxide film in which many of these are collected is considered to be a more preferable film.
以上のような方法により形成された酸化チタン膜は、微細な酸化チタン粒子からなり、緻密な密着性のよいものとなる。 The titanium oxide film formed by the method as described above is composed of fine titanium oxide particles and has good dense adhesion.
以下、本発明の実施例についてより詳しく説明する。なお、同一要素には同一符号を用い、重複する説明は省略する。 Hereinafter, examples of the present invention will be described in more detail. In addition, the same code | symbol is used for the same element and the overlapping description is abbreviate | omitted.
［概要］
図１（ａ）において、本発明の実施例の手順をフローチャートで示す。ここで述べる実施例は、電極や電解質等の準備工程（Ｓ１２）と、泳動電着法（ＥＰＤ：ＥｌｅｃｔｒｏＰｈｏｒｅｔｉｃ Ｄｅｐｏｓｉｔｉｏｎ）を用いた成膜工程（Ｓ１３）と、電極に付着した膜を焼付ける焼結工程（Ｓ１４）から構成される。即ち、種々の固体濃度及び形状からなる酸化チタン（例えば、ＴｉＯ２）ナノ粒子コーティング層が、泳動電着法によって、ミクロンサイズの径を持つステンレス鋼製のワイヤーメッシュ（基板）上に形成された。泳動電着法（ＥＰＤ）において、一般に溶媒液中に分散又は懸濁している正（又は負）の荷電粒子は逆の負（又は正）の荷電した基材に引き付けられて堆積する。堆積した層の構造は、水性懸濁液（ＴｉＯ２−ＳＡ系）および非水分散液（ＴｉＯ２−ＩＰＡ系）において、異なる荷電方法を用いて制御された。
[Overview]
FIG. 1A is a flowchart showing the procedure of the embodiment of the present invention. In the embodiment described here, a preparation step (S12) of an electrode, an electrolyte, etc., a film formation step (S13) using an electrophoretic deposition method (EPD), and a sintering for baking a film attached to the electrode It consists of a process (S14). That is, titanium oxide (for example, TiO 2 ) nanoparticle coating layers having various solid concentrations and shapes were formed on a stainless steel wire mesh (substrate) having a micron-sized diameter by electrophoretic deposition. . In electrophoretic electrodeposition (EPD), generally positive (or negative) charged particles dispersed or suspended in a solvent solution are attracted to and deposited on an opposite negative (or positive) charged substrate. Structure of the deposited layers, an aqueous suspension (TiO 2 -SA system) and a non-aqueous dispersion in (TiO 2 -IPA system) to be controlled using different charge methods.
［電極の準備］
図１（ｂ）に、カソードの電極の準備工程（Ｓ１２）を示す。ステンレス（ＳＵＳ３１６）製のメッシュ（基材）から、長さ１５ｍｍで、径ｄ＝０．２５ｍｍのロッドを切り出した（Ｓ２１）。このロッドを、５０℃の０．１Ｍ硫酸液中に浸漬し、３５ｋＨｚの超音波処理（エッチング）を１０分間行った（Ｓ２２）。その後水道水で洗浄して、超純水中で超音波により５分間洗浄を行った（Ｓ２３）。更に、アセトンで２分間洗浄し、１０分間自然乾燥した（Ｓ２４）。このロッドをカソードに用いた。また、アノードとして、純水及びアセトンでの洗浄を行ったアルミ板（５０ｍｍ×１５ｍｍ×２ｍｍ）を用いた。
[Preparation of electrode]
FIG. 1B shows a cathode electrode preparation step (S12). A rod having a length of 15 mm and a diameter d = 0.25 mm was cut out from a mesh (base material) made of stainless steel (SUS316) (S21). This rod was immersed in a 0.1 M sulfuric acid solution at 50 ° C., and subjected to ultrasonic treatment (etching) at 35 kHz for 10 minutes (S22). Then, it was washed with tap water, and was washed with ultrasonic waves for 5 minutes in ultrapure water (S23). Furthermore, it was washed with acetone for 2 minutes and then naturally dried for 10 minutes (S24). This rod was used as the cathode. Further, an aluminum plate (50 mm × 15 mm × 2 mm) cleaned with pure water and acetone was used as the anode.
［水系電解質の準備］
図３に本実施例で用いた泳動電着装置１０の概略図を示す。また、図１（ｃ）に酸化チタンの成膜工程を示す。電解質槽１２に、水系の電解質溶液２０として、２５％の高分子分散剤を含む有機系分散安定剤水溶液中に、総量３０％の酸化チタンのナノ粒子（ｒｅｃｅｉｖｅｄ ｃａｐｐｅｄ ｎａｎｏｓｉｚｅ ＴｉＯ２）２２を懸濁した原液を超純水で所定の割合で希釈したものを入れた（Ｓ３１）。この懸濁電解質溶液（ＴｉＯ２−ＳＡ系）の原液は、乳白色であり、とても安定した懸濁液であり、その粒子は数カ月放置しておいても当初のサイズを保持する。この原液において、ＴｉＯ２は、３０ｗｔ％であり、希釈後は、７．５ｗｔ％であった。この中に、上述の電極（アノード１４及びカソード１６）を浸漬し（Ｓ３２）、更に、ｐＨメータ及び温度計１８も浸漬し、泳動電着中のｐＨ及び温度のモニタを行った。成膜工程の前に電気泳動漕１２に２０分間超音波処理を行った。それぞれの電気泳動による粒子サイズの分布は、動的光散乱分析（Ｍａｌｖｅｒｎ Ｉｎｓｔｒｕｍｅｎｔ， ＨＰＰ ５００１）によって測定された。図２には、有機系電解質で用いたものを含めて、酸化チタンの粒径分布の測定結果を示す。酸化チタンが３０ｗｔ％含まれる原液においては、平均粒径は１０ｎｍ以下であり、水系電解質では、１００ｎｍくらいであり、有機系電解質では、１０００ｎｍ以上であった。
[Preparation of aqueous electrolyte]
FIG. 3 shows a schematic diagram of the electrophoretic electrodeposition apparatus 10 used in this example. FIG. 1C shows a titanium oxide film forming process. A total of 30% of titanium oxide nanoparticles (received capped nanosize TiO 2 ) 22 is suspended in the electrolyte bath 12 as an aqueous electrolyte solution 20 in an organic dispersion stabilizer aqueous solution containing 25% of a polymer dispersant. The stock solution diluted with ultrapure water at a predetermined ratio was added (S31). The stock solution of the suspension electrolyte solution (TiO 2 -SA system) is milky white and is a very stable suspension, and its particles retain their original size even after being left for several months. In this stock solution, TiO 2 was 30 wt%, and after dilution, 7.5 wt%. The above-mentioned electrodes (anode 14 and cathode 16) were immersed in this (S32), and further, a pH meter and a thermometer 18 were also immersed, and the pH and temperature during electrophoretic deposition were monitored. Before the film forming process, the electrophoretic basket 12 was subjected to ultrasonic treatment for 20 minutes. The particle size distribution by each electrophoresis was measured by dynamic light scattering analysis (Malvern Instrument, HPP 5001). FIG. 2 shows the measurement results of the particle size distribution of titanium oxide including those used in organic electrolytes. In the stock solution containing 30% by weight of titanium oxide, the average particle size was 10 nm or less, about 100 nm for the aqueous electrolyte, and 1000 nm or more for the organic electrolyte.
［水系泳動電着］
上述の電極及び電解質を用いて、６０ μＡ／ｃｍ２の電流密度でＥＰＤによる電着処理を行った。電着中の電流密度は、内製した回路３０により測定した。この回路は、デジタルマルチメーター（ＰＣ ５１０， Ｓａｎｗａ）によって、校正された。カソード側からの出力電流密度は、データロガー（Ｇｒａｐｈｔｅｃ）２４によって記録された。電着（ＥＰＤ）工程中、ｐＨプローブは電極間に配置され、電流密度と共にｐＨが測定された。各電極間の距離は一定の温度下で８ｍｍに維持された。電着は、パルス電圧を用いて１〜５分の範囲の幾つかの時間で何回か行われた（Ｓ３３）。その後、新しい泳動槽１２にて直流を用いて繰り返した（Ｓ３４、Ｓ３５）。パルス電圧の周期は、０．２５ｓ〜５０ｍｓの範囲で設定した。
[Water-based electrophoretic electrodeposition]
Electrodeposition treatment by EPD was performed at a current density of 60 μA / cm 2 using the above electrode and electrolyte. The current density during electrodeposition was measured by an in-house circuit 30. This circuit was calibrated with a digital multimeter (PC 510, Sanwa). The output current density from the cathode side was recorded by a Datalogger 24. During the electrodeposition (EPD) process, a pH probe was placed between the electrodes and the pH was measured along with the current density. The distance between each electrode was maintained at 8 mm at a constant temperature. Electrodeposition was performed several times using pulse voltage for several times ranging from 1 to 5 minutes (S33). Then, it repeated using direct current in the new migration tank 12 (S34, S35). The period of the pulse voltage was set in the range of 0.25 s to 50 ms.
図４（ａ）に、パルス電圧の模式図を示す。ベース電圧Ｖｂ（多くの場合０Ｖ）に対して、矩形波パルスの最大電圧Ｖｐを印加し（電圧差は、Ｖｐ−Ｖｂ）、それをＴｐ秒間継続して、ベース電圧Ｖｂに戻し、そのままＴｉ秒間保持して、再度最大電圧Ｖｐを印加した。尚、これと同様な効果を示すサインカーブを用いたパルス電圧の模式図を図４（ｂ）に示す。ベース電圧Ｖｂ（多くの場合０Ｖ）に対して、サイン波パルスの最大電圧Ｖｐを徐々に印加すると、ｔ１秒でベース電圧とは言えない程度（Ｖｂ１）まで電圧が上昇し、そして、ｔ２秒で実質的にピーク電圧といえる実効値（Ｖｐ１）まで電圧が上がり、ｔ３秒で真のピーク電圧Ｖｐまで上がり、その電圧上昇カーブを反転させたカーブで電圧がベース電圧Ｖｂまで下がり（ｔ４秒）、これで１つの周期を形成する。 FIG. 4A shows a schematic diagram of the pulse voltage. The maximum voltage Vp of the rectangular wave pulse is applied to the base voltage Vb (in many cases 0 V) (the voltage difference is Vp−Vb), and this is continued for Tp seconds, and then returned to the base voltage Vb, as it is for Ti seconds. The maximum voltage Vp was applied again. FIG. 4B shows a schematic diagram of a pulse voltage using a sine curve showing the same effect as this. When the maximum voltage Vp of the sine wave pulse is gradually applied to the base voltage Vb (in many cases 0 V), the voltage rises to a level (Vb1) that cannot be said to be the base voltage at t1 seconds, and at t2 seconds. The voltage rises to an effective value (Vp1) that can be said to be substantially the peak voltage, rises to the true peak voltage Vp at t3 seconds, and falls to the base voltage Vb in a curve obtained by inverting the voltage rise curve (t4 seconds) This forms one cycle.
より具体的には、次のような条件で電着を行った。ＴｉＯ２−ＳＡ系電気泳動槽の温度は、２７℃で、電圧は、〜５４ＤＣＶであった。また、パルス電圧での電着（ＥＰＤ）では、電流密度を−４０〜−３０Ａ／ｃｍ２とし、５分間行った。尚、電動槽１２の温度は、電着中２８〜３０℃の間で慎重に監視された。リファレンス基材は、電圧が印加されることなく泳動槽中に置かれた。 More specifically, electrodeposition was performed under the following conditions. The temperature of the TiO 2 -SA electrophoresis tank was 27 ° C., and the voltage was ˜54 DCV. Further, in electrodeposition (EPD) with a pulse voltage, the current density was set to −40 to −30 A / cm 2 for 5 minutes. In addition, the temperature of the electric tank 12 was carefully monitored between 28-30 degreeC during electrodeposition. The reference substrate was placed in the electrophoresis bath without applying voltage.
図４（ａ）を用いてより詳細に述べれば、ベース電圧Ｖｂを０Vとし、最大電圧Ｖｐを約５４Ｖとし、Ｖｐを維持する時間Ｔｐは、周期となるＴｔの半分、即ち、ベース電圧Ｖｂとする時間Ｔｉと同じとなるようにした。Ｔｔとしては、本実験では２５ｍｓｅｃ（ｍ秒）、１００ｍｓｅｃ、４００ｍｓｅｃの３種類（これらはそれぞれ、４０Ｈｚ、１０Ｈｚ、２．５Ｈｚに相当）を行った。比較例としては、最大電圧Ｖｐを約５４Ｖとして継続して印加した直流実験も行った。 More specifically using FIG. 4A, the base voltage Vb is set to 0V, the maximum voltage Vp is set to about 54V, and the time Tp for maintaining Vp is half of the period Tt, that is, the base voltage Vb. It was made to become the same as Ti to do. In this experiment, three types of Tt of 25 msec (msec), 100 msec, and 400 msec (these correspond to 40 Hz, 10 Hz, and 2.5 Hz, respectively) were performed. As a comparative example, a direct current experiment was also performed in which the maximum voltage Vp was continuously applied at about 54V.
［焼結工程］
図１（ｄ）に酸化チタン膜の焼結工程を示す。酸化チタンが電着された基材は、プログラム制御可能な炉の中で２．５℃／分のレートで加熱し、５５０℃で４．５時間保持した（Ｓ４２）。その後、炉から取出し膜の特性を測定した（Ｓ４３）。平均膜厚は数百nmオーダーであった。
[Sintering process]
FIG. 1D shows a sintering process of the titanium oxide film. The base material electrodeposited with titanium oxide was heated at a rate of 2.5 ° C./min in a programmable furnace and held at 550 ° C. for 4.5 hours (S42). Thereafter, the characteristics of the film taken out from the furnace were measured (S43). The average film thickness was on the order of several hundred nm.
［水系泳動電結果］
図５は、パルス周期Ｔｔを２５ｍｓｅｃとして行ったものと、一定の電圧のものについて、水系電解質中の電着における見かけの電流密度の経時変化をプロットするグラフである。菱形のプロットは、パルス電圧で電着を行ったときの経時変化を、四角のプロットは、一定の電圧下で電着を行ったときの経時変化をそれぞれ示している。この図からわかるように、一定電圧の直流方式では、電流密度が最初直線的に減少し、その後やや傾きをなだらかにしながらも、電流密度は次第に小さくなっている。一方、パルス電圧をかけるパルス電流方式では、電流密度は最初大きく落ち込むが、その後なだらかに上昇した。このグラフから、直流方式では、電極が非導電性の被膜に覆われ電流が小さくなったと考えられ、一方、パルス電流方式では、ナノサイズの酸化チタンにのみ覆われるので、電極の有効面積が極端に小さくなることがないと考えられる。
[Aqueous electrophoresis result]
FIG. 5 is a graph plotting the change over time in the apparent current density in electrodeposition in an aqueous electrolyte, for a pulse period Tt of 25 msec and for a constant voltage. The rhombus plot shows the change over time when electrodeposition was performed with a pulse voltage, and the square plot shows the change over time when electrodeposition was performed under a constant voltage. As can be seen from the figure, in the DC method with a constant voltage, the current density first decreases linearly, and then the current density gradually decreases with a slight inclination. On the other hand, in the pulse current method in which a pulse voltage is applied, the current density drops greatly at first, but then gradually increases. From this graph, it is considered that in the DC method, the electrode was covered with a non-conductive film and the current was reduced, while in the pulse current method, the electrode was covered only with nano-sized titanium oxide, so the effective area of the electrode was extremely small. It is thought that it will not become smaller.
図６は、本実施例で成膜し、焼結させた酸化チタンの粉末Ｘ線回折装置（理学電気株式会社製）のＫαによる粉末Ｘ線回折測定結果を示す。図からわかるように、酸化チタンは主にアナターゼ型であった。また、膜の形態を、電界放出型走査型電子顕微鏡（ＦＥ−ＳＥＭ）によって加速電圧６ｋＶで観察した。図７は、直流方式の場合とパルス電流方式の場合の膜の形態のＳＥＭ写真を示す。この写真から、パルス電流方式の方がより多くの酸化チタンを成膜していることがわかる。 FIG. 6 shows a powder X-ray diffraction measurement result by Kα of a titanium oxide powder X-ray diffraction apparatus (manufactured by Rigaku Corporation) formed and sintered in this example. As can be seen from the figure, titanium oxide was mainly anatase type. Moreover, the form of the film was observed at an acceleration voltage of 6 kV by a field emission scanning electron microscope (FE-SEM). FIG. 7 shows SEM photographs of film forms in the direct current method and the pulse current method. From this photograph, it can be seen that more titanium oxide is deposited in the pulse current method.
また、エネルギー分散型Ｘ線マイクロアナライザーにより、ステンレス基材、直流方式酸化チタン膜、パルス電流方式酸化チタン膜のそれぞれの成分を測定した。基材のステンレス成分を基準に考えれば、相対的にチタン成分の量を把握することができ、直流方式酸化チタン膜よりも、パルス電流方式酸化チタン膜の方がより多くのチタンを含んでいることがわかる。従って、パルス電流方式の方が、成膜量が多く、成膜速度が高いことがわかる（表１参照）。 Moreover, each component of the stainless steel substrate, the direct current system titanium oxide film, and the pulse current system titanium oxide film was measured with an energy dispersive X-ray microanalyzer. Considering the stainless steel component of the base material as a reference, the amount of the titanium component can be grasped relatively, and the pulse current system titanium oxide film contains more titanium than the direct current system titanium oxide film. I understand that. Therefore, it can be seen that the pulse current method has a larger film formation amount and a higher film formation speed (see Table 1).
［有機系電解質の準備］
図３に示す同じ装置を用いた。電解質槽１２に、平均粒径２０ｎｍのデグサＰ２５の酸化チタン粉末を、２−プロパノールに混ぜて、酸化チタンが約１．２５ｗｔ％の電解質（ＴｉＯ２−ＩＰＡ系）を入れた。ＴｉＯ２−ＩＰＡ系は、粘着性があり乳白色で、あまり安定した懸濁液ではなく、粒子は超音波処理をした後、２〜４時間だけしか懸濁状態を維持できなかった。電気泳動漕１２は４グラムのＰ２５の酸化チタン粉末を３１４グラムの２−プロパノールに混ぜて用意され、電着工程の前に電解質槽１２で２０分間超音波処理を行った。図２にあるように、動的光散乱分析（Ｍａｌｖｅｒｎ Ｉｎｓｔｒｕｍｅｎｔ， ＨＰＰ ５００１）によって粒子分布が測定された。
[Preparation of organic electrolyte]
The same apparatus shown in FIG. 3 was used. In the electrolyte tank 12, titanium oxide powder of Degussa P25 having an average particle diameter of 20 nm was mixed with 2-propanol, and an electrolyte (TiO 2 -IPA system) containing about 1.25 wt% titanium oxide was placed. The TiO 2 -IPA system was sticky, milky white and not a very stable suspension, and the particles could only remain in suspension for 2 to 4 hours after sonication. The electrophoresis basket 12 was prepared by mixing 4 grams of P25 titanium oxide powder with 314 grams of 2-propanol, and sonicated in the electrolyte bath 12 for 20 minutes before the electrodeposition process. As shown in FIG. 2, the particle distribution was measured by dynamic light scattering analysis (Malvern Instrument, HPP 5001).
［有機系泳動電着］
上述の電極及び電解質を用いて、４０ μＡ／ｃｍ２の電流密度で、水系泳動電着と同様に電着処理を行った。電着中の電流密度は、内製した回路３０により測定した。この回路は、デジタルマルチメーター（ＰＣ ５１０， Ｓａｎｗａ）によって、校正された。カソード側からの出力電流密度は、データロガー（Ｇｒａｐｈｔｅｃ）２４によって記録された。電着（ＥＰＤ）工程中、ｐＨプローブは電極間に配置され、電流密度と共にｐＨが測定された。各電極間の距離は一定の温度下で８ｍｍに維持された。電着は、パルス電圧を用いて１〜５分の範囲の幾つかの時間で何回か行われた（Ｓ３３）。その後、新しい泳動槽１２にて直流を用いて繰り返した（Ｓ３４）。パルス電圧のピーク間の時間は、０．２５ｓ〜５０ｍｓの範囲で設定した。より具体的には、次のような条件で電着を行った。ＴｉＯ２−ＩＰＡ系電気泳動槽の温度は、２７℃で、電圧は、〜５４ＤＣＶであった。また、パルス電圧での電着（ＥＰＤ）では、電流密度を−２６〜−２０ｍＡ／ｃｍ２、２．５分間行った。尚、電動槽１２の温度は、電着中２８〜３０℃の間で慎重に監視された。リファレンス基材は、荷電されることなく泳動槽中に置かれた。
[Organic electrophoretic electrodeposition]
Electrodeposition treatment was performed using the above-described electrode and electrolyte at a current density of 40 μA / cm 2 in the same manner as aqueous electrophoretic electrodeposition. The current density during electrodeposition was measured by an in-house circuit 30. This circuit was calibrated with a digital multimeter (PC 510, Sanwa). The output current density from the cathode side was recorded by a Datalogger 24. During the electrodeposition (EPD) process, a pH probe was placed between the electrodes and the pH was measured along with the current density. The distance between each electrode was maintained at 8 mm at a constant temperature. Electrodeposition was performed several times using pulse voltage for several times ranging from 1 to 5 minutes (S33). Then, it repeated using direct current in the new migration tank 12 (S34). The time between the peaks of the pulse voltage was set in the range of 0.25 s to 50 ms. More specifically, electrodeposition was performed under the following conditions. The temperature of the TiO 2 -IPA electrophoresis tank was 27 ° C., and the voltage was ˜54 DCV. In electrodeposition (EPD) with a pulse voltage, the current density was −26 to −20 mA / cm 2 for 2.5 minutes. In addition, the temperature of the electric tank 12 was carefully monitored between 28-30 degreeC during electrodeposition. The reference substrate was placed in the electrophoresis bath without being charged.
ここで、同様に図４（ａ）を用いてより詳細に述べれば、ベース電圧Ｖｂを０Vとし、最大電圧Ｖｐを約１０Ｖとし、Ｖｐを維持する時間Ｔｐは、周期となるＴｔの半分、即ち、ベース電圧Ｖｂとする時間Ｔｉと同じとなるようにした。Ｔｔとしては、本実験では２５ｍｓｅｃ（ｍ秒）、１００ｍｓｅｃ、４００ｍｓｅｃの３種類（これらはそれぞれ、４０Ｈｚ、１０Ｈｚ、２．５Ｈｚに相当）を行った。比較例としては、最大電圧Ｖｐを約１０Ｖとして継続して印加した直流実験も行った。 Similarly, in more detail using FIG. 4A, the base voltage Vb is set to 0V, the maximum voltage Vp is set to about 10V, and the time Tp for maintaining Vp is half of the period Tt, that is, The time Ti for setting the base voltage Vb is the same as the time Ti. In this experiment, three types of Tt of 25 msec (msec), 100 msec, and 400 msec (these correspond to 40 Hz, 10 Hz, and 2.5 Hz, respectively) were performed. As a comparative example, a direct current experiment in which the maximum voltage Vp was continuously applied at about 10 V was also performed.
［焼結工程］
電着を止めた後に、基材をゆっくりと引き上げて５０℃の温浴に１０分間浸した。浸すプロセスにおいて酸化チタンが成膜した基材は、非常にゆっくり引き上げ、浸すことが好ましい。５０℃のお湯に１０分間浸漬されて、洗浄された（Ｓ４１）。その後、プログラム制御可能な炉の中で２．５℃／分のレートで加熱し、５５０℃で４．５時間保持した（Ｓ４２）。その後、炉から取出し膜の特性を測定した（Ｓ４３）。平均膜厚は数１０μｍであった。
[Sintering process]
After stopping the electrodeposition, the substrate was slowly pulled up and immersed in a 50 ° C. warm bath for 10 minutes. The substrate on which the titanium oxide film is formed in the dipping process is preferably pulled up and dipped very slowly. It was immersed in hot water of 50 ° C. for 10 minutes and washed (S41). Then, it heated at the rate of 2.5 degree-C / min in the furnace which can be controlled, and hold | maintained at 550 degreeC for 4.5 hours (S42). Thereafter, the characteristics of the film taken out from the furnace were measured (S43). The average film thickness was several tens of μm.
［有機系泳動電着結果］
図９は、パルス周期Ｔｔを２５ｍｓｅｃとして行ったものと、一定の電圧のものについて、水系電解質中の電着における見かけの電流密度の経時変化をプロットするグラフである。菱形のプロットは、パルス電圧で電着を行ったときの経時変化を、四角のプロットは、一定の電圧下で電着を行ったときの経時変化をそれぞれ示している。この図からわかるように、一定電圧の直流方式及びパルス電圧のパルス電流方式のいずれでも、電流密度が最初直線的に減少し、その後やや傾きをなだらかにしながらも、電流密度は次第に小さくなっている。とくに、直流方式がその電流密度が小さかった。
[Results of organic electrophoretic electrodeposition]
FIG. 9 is a graph plotting the change over time of the apparent current density in electrodeposition in an aqueous electrolyte, for the case where the pulse period Tt is 25 msec and for the case where the voltage is constant. The rhombus plot shows the change over time when electrodeposition was performed with a pulse voltage, and the square plot shows the change over time when electrodeposition was performed under a constant voltage. As can be seen from this figure, in both the constant voltage direct current method and the pulsed voltage pulse current method, the current density first decreases linearly, and then the current density gradually decreases with a slight slope. . In particular, the direct current method has a low current density.
図１０は、電極として用いた酸処理したステンレスロッドの表面の形態及び本実施例で成膜した膜の形態を、電界放出型走査型電子顕微鏡（ＦＥ−ＳＥＭ）によって加速電圧６ｋＶで観察した。 In FIG. 10, the form of the surface of the acid-treated stainless rod used as an electrode and the form of the film formed in this example were observed with a field emission scanning electron microscope (FE-SEM) at an acceleration voltage of 6 kV.
また、エネルギー分散型Ｘ線マイクロアナライザーにより、ステンレス基材、直流方式酸化チタン膜、パルス電流方式酸化チタン膜のそれぞれの成分を測定した。基材のステンレス成分を基準に考えれば、相対的にチタン成分の量を把握することができ、直流方式酸化チタン膜よりも、パルス電流方式酸化チタン膜の方がより多くのチタンを含んでいることがわかる。従って、パルス電流方式の方が、成膜量が多く、成膜速度が高いことがわかる（表２参照）。 Moreover, each component of the stainless steel substrate, the direct current system titanium oxide film, and the pulse current system titanium oxide film was measured with an energy dispersive X-ray microanalyzer. Considering the stainless steel component of the base material as a reference, the amount of the titanium component can be grasped relatively, and the pulse current system titanium oxide film contains more titanium than the direct current system titanium oxide film. I understand that. Therefore, it can be seen that the pulse current method has a larger film formation amount and a higher film formation speed (see Table 2).
酸化チタン（ＴｉＯ２）電着ステンレスロッドが、ＴｉＯ２−ＳＡ系（界面活性剤あり）、及びＴｉＯ２−ＩＰＡ系（界面活性剤なし）について、直流方式及びパルス電流方式により得られた。パルス電流方式の電着は、オフの期間（電圧が課されない期間）に、カソードの回りに粒子のスクリーニングが少なくなるので、好ましい。非水系の電解質に比べて、界面活性剤のせいで、水系電解質はより高い電圧が必要であろう。パルス電圧によるパルス電流方式の電着は、薄膜コーティングにおいて好ましい。非水系の電解質において、薄い及び厚いコーティング層に対して、直流方式及びパルス電流方式のいずれも好ましい。 Titanium oxide (TiO 2) electrodeposition stainless rod, TiO 2 -SA system (with surfactant), and TiO 2 -IPA system for (without surfactant) was obtained by the DC method and the pulse current method. Pulsed current electrodeposition is preferred because it reduces screening of particles around the cathode during the off period (period when no voltage is applied). Compared to non-aqueous electrolytes, aqueous electrolytes may require higher voltages due to surfactants. Pulse current type electrodeposition by pulse voltage is preferred for thin film coating. In a non-aqueous electrolyte, both the direct current method and the pulse current method are preferable for the thin and thick coating layers.
懸濁液として、市販のポリスチレン（ラテックス）ＰＳＬ粒子の原液（懸濁液）を純水（ｍｉｌｌｉｐｏｒｅ ｗａｔｅｒ：代表的な抵抗率は、１０−１５ＭΩ・ｃｍである）で希釈して、以下の実験に用いた。このＰＳＬは一般に粒子径の標準として用いられ、粒子径分布は非常にシャープである。いうなれば、単分散である。より具体的には、粒子径が５０ｎｍ（約１ｗｔ％）と３００ｎｍ（約１０ｗｔ％）のＰＳＬ粒子を含む原液をそれぞれ用い、上記純水で希釈した。動的光散乱法を用いて、それぞれの懸濁液の水中粒子径分布を確認したところ、５０ｎｍと３００ｎｍにそれぞれ粒子径ピークを現すことが分かった。このようにそれぞれ単位体積あたりほぼ同数と考えられるＰＳＬ粒子を含む希釈懸濁液を調製し、それらを混合した。この混合液に対して、１０分間、超音波分散機によって分散を行ってから、以下に述べる電気泳動を行った。 As a suspension, a stock solution (suspension) of commercially available polystyrene (latex) PSL particles was diluted with pure water (typical resistivity is 10-15 MΩ · cm), and the following experiment was performed. Used for. This PSL is generally used as a particle size standard, and the particle size distribution is very sharp. In other words, it is monodisperse. More specifically, stock solutions containing PSL particles having particle diameters of 50 nm (about 1 wt%) and 300 nm (about 10 wt%) were respectively used and diluted with the pure water. When the particle size distribution in water of each suspension was confirmed using the dynamic light scattering method, it was found that particle size peaks appeared at 50 nm and 300 nm, respectively. Thus, diluted suspensions containing PSL particles considered to be approximately the same per unit volume were prepared and mixed. The mixture was dispersed with an ultrasonic disperser for 10 minutes and then subjected to electrophoresis described below.
電気泳動は、上述の実施例１と同じく、図３に示す装置で、水温２６℃で２分間行った。電流モードは、直流の他に５Ｈｚから４０Ｈｚ（２５ｍｓから２００ｍｓ）のパルス電流の２種類を行った。電気泳動の結果、粒子が堆積した基板を、６０℃の乾燥機で、２時間乾燥を行った。 The electrophoresis was carried out at the water temperature of 26 ° C. for 2 minutes using the apparatus shown in FIG. 3 as in Example 1 described above. In the current mode, two types of pulse current of 5 Hz to 40 Hz (25 ms to 200 ms) were performed in addition to direct current. As a result of electrophoresis, the substrate on which the particles were deposited was dried with a dryer at 60 ° C. for 2 hours.
図１２は、粒子が堆積された基板について、電子顕微鏡（ＪＥＯＬ−ＪＳＭ６３３５Ｆ， ＦＥ−ＳＥＭ）を用いて、形態観察を行った結果を示す。この図において、（ａ）左側は２５ｍｓのパルス電流を用いた場合の粒子の堆積状態を表し、（ｂ）右側は直流を用いた場合の粒子の堆積状態を表す。何れの場合も集積時間は、２分間である。何れの場合も、上述のように粒子径が５０ｎｍと３００ｎｍの水中ポリスチレン粒子（混合した懸濁液）を使用した。 FIG. 12 shows the results of morphological observation of a substrate on which particles are deposited, using an electron microscope (JEOL-JSM6335F, FE-SEM). In this figure, (a) the left side represents the particle deposition state when a pulse current of 25 ms is used, and (b) the right side represents the particle deposition state when direct current is used. In either case, the integration time is 2 minutes. In either case, as described above, polystyrene particles in water (mixed suspension) having a particle size of 50 nm and 300 nm were used.
図１２には、パルス電流モードおよび直流モードでの電気泳動によって粒子が基板上に堆積した様子を示す。図１２（ａ）に「５０ｎｍ」及び「３００ｎｍ」で示す円内に見えるものが、それぞれの径の粒子である。両モードのいずれの場合でも、粒子径が小さい（５０ｎｍ）場合では、凝集が見られない。しかし、図１２（ｂ）の直流モードにおいて、粒子径が大きい（３００ｎｍ）粒子では、若干凝集しているように見える（図中ほぼ中央に円で囲った３つの粒子を参照）。数枚の電子顕微鏡の結果から、基板に堆積された（３００ｎｍ）粒子の凝集状態を数値化してみた。 FIG. 12 shows a state where particles are deposited on the substrate by electrophoresis in the pulse current mode and the direct current mode. What is visible in the circles indicated by “50 nm” and “300 nm” in FIG. In both cases, no aggregation is observed when the particle size is small (50 nm). However, in the direct current mode of FIG. 12B, the particles having a large particle size (300 nm) appear to be slightly agglomerated (see three particles surrounded by a circle in the center in the figure). From the results of several electron microscopes, the state of aggregation of particles (300 nm) deposited on the substrate was quantified.
その結果を図１３に示す。横軸に示す数値は、凝集状態と考えられる粒子集合体の構成粒子の数である。横軸の各数値毎に４種類の棒グラフがあり、左から２５ｍｓ，５０ｍｓ，２００ｍｓの周期を持つパルス電流により、そして、直流電流（ＤＣ）により電気泳動実験を行ったものの結果である。各棒グラフの高さ（即ち、縦軸）は、各実験において、そのような状態にある粒子集合体の数を示す。即ち、凝集したと認められる集合体に含まれる粒子の数を横軸に、その頻度（個数）を縦軸に取ったグラフである。例えば、横軸が１の場合は、粒子個数が１であるので、基板に堆積した粒子は凝集していない。横軸が２の場合は、２個の粒子が凝集しており、３の場合は３個、４の場合は４個としている。従って、横軸で数が大きくなると凝集径が大きくなる。尚、この計測は電子顕微鏡写真から、上述の基準に従い粒子の数を数えることにより行った。 The result is shown in FIG. The numerical value shown on the horizontal axis is the number of constituent particles of the particle aggregate considered to be in an aggregated state. There are four types of bar graphs for each numerical value on the horizontal axis, which are the results of performing electrophoresis experiments with pulse currents having a period of 25 ms, 50 ms, and 200 ms from the left, and with direct current (DC). The height of each bar graph (ie, the vertical axis) indicates the number of particle aggregates in such a state in each experiment. That is, it is a graph in which the horizontal axis represents the number of particles contained in the aggregate recognized as agglomerated and the frequency (number) thereof represents the vertical axis. For example, when the horizontal axis is 1, since the number of particles is 1, the particles deposited on the substrate are not aggregated. When the horizontal axis is 2, two particles are aggregated. When the horizontal axis is 3, the number is 3, and when the number is 4, the number is 4. Therefore, the larger the number on the horizontal axis, the larger the aggregate diameter. This measurement was performed by counting the number of particles from an electron micrograph according to the above-mentioned criteria.
ここで、特に孤立した粒子（凝集しない粒子）の個数に着目すると、５０ｍｓ（２０Ｈｚ）のパルス電流で行った電気泳動が最も孤立粒子の個数が少なく、グラフの目盛りで、約１２であった。横軸の数値が６や７の所を見れば、この５０ｍｓの条件では、粒子数が６個または７個までの凝集粒子の存在を確認できる。つまり、この条件は、最も孤立粒子の個数の少ないものであり、より高い凝集状態を生じ易いものであることがわかる。その次に、孤立粒子（凝集しない粒子）の個数が少なかったのは、２００ｍｓ（５Ｈｚ）のパルスの場合であり、グラフの目盛りで、約２２であった。また、直流電流（ＤＣ）の場合は、グラフの目盛りで、約３０であった。今回の実験では、最も孤立粒子を多く形成できる条件が、２５ｍｓ（４０Ｈｚ）のパルス電流であることが分かった。これにより、パルス電気泳動において、本実験において、（４０Ｈｚ）が最適な条件であると考えられる。即ち、電気泳動を所定の周期のパルス電流で行うことにより、粒子の分散状態を維持可能であることがわかり、更に、考察すれば、粒子の分散を促進するような電気泳動の特定の範囲の周期のパルス電流が存在することが理解できる。実験条件により、このような周期のパルス電流の範囲が変わることは予想されるが、パルス電流の周期という比較的容易に制御できる条件で、所望の分散状態を得ることが出来得ることがわかった。 Here, focusing on the number of isolated particles (particles that do not aggregate), electrophoresis performed with a pulse current of 50 ms (20 Hz) had the smallest number of isolated particles, and the scale of the graph was about 12. If the numerical value on the horizontal axis is 6 or 7, the presence of aggregated particles up to 6 or 7 particles can be confirmed under the condition of 50 ms. That is, it can be seen that this condition is the one with the smallest number of isolated particles and is likely to cause a higher aggregation state. Next, the number of isolated particles (particles that did not aggregate) was small in the case of a pulse of 200 ms (5 Hz), which was about 22 on the scale of the graph. In the case of direct current (DC), it was about 30 on the scale of the graph. In this experiment, it was found that the pulse current of 25 ms (40 Hz) was the most capable of forming isolated particles. Thereby, in pulse electrophoresis, (40 Hz) is considered to be the optimum condition in this experiment. That is, it can be seen that the state of dispersion of particles can be maintained by performing electrophoresis with a pulse current of a predetermined cycle. Further, when considered, a specific range of electrophoresis that promotes dispersion of particles is considered. It can be seen that there is a periodic pulse current. Although it is expected that the range of the pulse current of such a period will change depending on the experimental conditions, it was found that the desired dispersion state can be obtained under the condition that the period of the pulse current can be controlled relatively easily. .
１０ 泳動電着装置
１２ 電解質槽
１４ アノード
１６ カソード
１８ ｐＨメータ及び温度計
２０ 電解質
２２ 酸化チタン粒子
２４ データロガー
３０ 回路
DESCRIPTION OF SYMBOLS 10 Electrophoretic electrodeposition apparatus 12 Electrolyte tank 14 Anode 16 Cathode 18 pH meter and thermometer 20 Electrolyte 22 Titanium oxide particle 24 Data logger 30 Circuit
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009069155A JP2009256790A (en) | 2008-03-19 | 2009-03-19 | Coating method of titanium oxide |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008072596 | 2008-03-19 | ||
| JP2009069155A JP2009256790A (en) | 2008-03-19 | 2009-03-19 | Coating method of titanium oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2009256790A true JP2009256790A (en) | 2009-11-05 |
Family
ID=41384559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2009069155A Pending JP2009256790A (en) | 2008-03-19 | 2009-03-19 | Coating method of titanium oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2009256790A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102154675A (en) * | 2011-03-07 | 2011-08-17 | 南京工业大学 | Preparation method of metal ceramic composite membrane |
| JP2012148354A (en) * | 2011-01-17 | 2012-08-09 | Suncall Corp | Method of manufacturing fixed abrasive grain wire |
| JP2015160892A (en) * | 2014-02-27 | 2015-09-07 | 独立行政法人国立高等専門学校機構 | Antifouling composite coat with biofilm forming ability suppressed |
| JP2015531816A (en) * | 2012-06-29 | 2015-11-05 | ノースイースタン ユニバーシティ | Three-dimensional crystalline, homogeneous and composite nanostructures prepared by field-induced assembly of nanoelements |
| JP2020028869A (en) * | 2018-08-24 | 2020-02-27 | 時空化学株式会社 | Method for producing voc removal catalyst, voc removal catalyst, and voc removal method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1018083A (en) * | 1996-07-01 | 1998-01-20 | Nippon Parkerizing Co Ltd | Production of metal material coated with titanium oxide |
| JP2003089896A (en) * | 2001-09-18 | 2003-03-28 | Ricoh Co Ltd | Particle arraying method, and particle arraying device manufactured by the method |
| JP2006297230A (en) * | 2005-04-18 | 2006-11-02 | Tokyo Institute Of Technology | Titanium oxide thin film, titanium oxide thin film-containing photocatalytic material, its manufacturing method, apparatus for cleaning water by using photocatalyst, and method for cleaning water by using photocatalytic reaction |
-
2009
- 2009-03-19 JP JP2009069155A patent/JP2009256790A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1018083A (en) * | 1996-07-01 | 1998-01-20 | Nippon Parkerizing Co Ltd | Production of metal material coated with titanium oxide |
| JP2003089896A (en) * | 2001-09-18 | 2003-03-28 | Ricoh Co Ltd | Particle arraying method, and particle arraying device manufactured by the method |
| JP2006297230A (en) * | 2005-04-18 | 2006-11-02 | Tokyo Institute Of Technology | Titanium oxide thin film, titanium oxide thin film-containing photocatalytic material, its manufacturing method, apparatus for cleaning water by using photocatalyst, and method for cleaning water by using photocatalytic reaction |
Non-Patent Citations (1)
| Title |
|---|
| JPN6013019736; Ｍ．Ｎａｚｌｉ Ｎａｉｍ， Ｍａｓａｈｉｋｏ Ｋｕｗａｔａ， Ｈｉｄｅｈｉｒｏ Ｋａｍｉｙａ， Ｉ． Ｗｕｌｅｄ Ｌｅｎｇｇｏｒｏ: 'Ｄｅｐｏｓｉｔｉｏｎ ｏｆ ＴｉＯ２ ｎａｎｏｐａｒｔｉｃｌｅｓ ｉｎ ｓｕｒｆａｃｔａｎｔ-ｃｏｎｔａｉｎｉｎｇ ａｑｕｅｏｕｓ ｓｕｓｐｅｎｔｉｏｎ ｂｙ ａ ｐｕｌｓｅｄ ＤＣ ｃｈａｒｇｉｎｇ' Ｊｏｕｒｎａｌ ｏｆ ｔｈｅ Ｃｅｒａｍｉｃ Ｓｏｃｉｅｔｙ ｏｆ Ｊａｐａｎ １１７／１, 20090101, １２７-１３２, Ｔｈｅ Ｃｅｒａｍｉｃ Ｓｏｃｉｅｔｙ ｏｆ Ｊａｐａｎ * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012148354A (en) * | 2011-01-17 | 2012-08-09 | Suncall Corp | Method of manufacturing fixed abrasive grain wire |
| CN102154675A (en) * | 2011-03-07 | 2011-08-17 | 南京工业大学 | Preparation method of metal ceramic composite membrane |
| JP2015531816A (en) * | 2012-06-29 | 2015-11-05 | ノースイースタン ユニバーシティ | Three-dimensional crystalline, homogeneous and composite nanostructures prepared by field-induced assembly of nanoelements |
| JP2015160892A (en) * | 2014-02-27 | 2015-09-07 | 独立行政法人国立高等専門学校機構 | Antifouling composite coat with biofilm forming ability suppressed |
| JP2020028869A (en) * | 2018-08-24 | 2020-02-27 | 時空化学株式会社 | Method for producing voc removal catalyst, voc removal catalyst, and voc removal method |
| JP7337338B2 (en) | 2018-08-24 | 2023-09-04 | 時空化学株式会社 | Method for producing catalyst for removing VOC and method for removing VOC |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Meng et al. | Effects of applied voltages on hydroxyapatite coating of titanium by electrophoretic deposition | |
| JP4563686B2 (en) | Deposition methods for nanostructured materials | |
| Anitha et al. | Biofilm formation on a TiO2 nanotube with controlled pore diameter and surface wettability | |
| Velichenko et al. | Electrodeposition PbO2–TiO2 and PbO2–ZrO2 and its physicochemical properties | |
| Radice et al. | Critical particle concentration in electrophoretic deposition | |
| WO2012116034A1 (en) | Electrophoretic-deposited surfaces | |
| Kalinina et al. | The influence of nanoparticle aggregation on formation of ZrO2 electrolyte thin films by electrophoretic deposition | |
| JP2009256790A (en) | Coating method of titanium oxide | |
| Hasanpoor et al. | In-situ study of mass and current density for electrophoretic deposition of zinc oxide nanoparticles | |
| Zhang et al. | Semiquantitative performance and mechanism evaluation of carbon nanomaterials as cathode coatings for microbial fouling reduction | |
| Zhang et al. | Effect of Zr addition on the microstructure and tribological property of the anodization of Ti-6Al-4V alloy | |
| Naim et al. | Electrophoretic packing structure from aqueous nanoparticle suspension in pulse DC charging | |
| Alavi et al. | Electrophoretic deposition of electroless nickel coated YSZ core-shell nanoparticles on a nickel based superalloy | |
| Dumitriu et al. | The electrochemical formation and shielding mechanism of TiO2 nanotubes in organic electrolytes with different viscosity | |
| Seuss et al. | Electrophoretic deposition of PEEK-TiO2 composite coatings on stainless steel | |
| MacLucas et al. | Surface protection of austenitic steels by carbon nanotube coatings | |
| Naim et al. | Electrostatic deposition of aerosol particles generated from an aqueous nanopowder suspension on a chemically treated substrate | |
| US20080224104A1 (en) | Method for Preparation of Stable Metal Oxide Nanoparticles Suspensions | |
| Chamanzadeh et al. | Self-organized and uniform TiO2 nanotube arrays with optimized NH4F concentration in electrolyte by high voltage electrochemical anodization | |
| Radice et al. | Methods for functionalization of microsized polystyrene beads with titania nanoparticles for cathodic electrophoretic deposition | |
| Naim et al. | Deposition of TiO2 nanoparticles in surfactant-containing aqueous suspension by a pulsed DC charging-mode electrophoresis | |
| Danookdharree et al. | The effect of initial etching sites on the morphology of TiO2 nanotubes on Ti-6Al-4V alloy | |
| Yoshida et al. | Synthesis of metallic zinc nanoparticles by electrolysis | |
| Molaei et al. | Electrophoretic deposition of nanobiocomposites for orthopedic applications: influence of contained water in suspension | |
| Meier et al. | Formation of Cu and Ni nanowires by electrodeposition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20120319 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20130123 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20130501 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20131029 |