JPS6333660B2 - - Google Patents
Info
- Publication number
- JPS6333660B2 JPS6333660B2 JP55170338A JP17033880A JPS6333660B2 JP S6333660 B2 JPS6333660 B2 JP S6333660B2 JP 55170338 A JP55170338 A JP 55170338A JP 17033880 A JP17033880 A JP 17033880A JP S6333660 B2 JPS6333660 B2 JP S6333660B2
- Authority
- JP
- Japan
- Prior art keywords
- crucible
- pyrolytic graphite
- coating
- graphite
- pyrographite
- 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.)
- Expired
Links
- 238000000576 coating method Methods 0.000 claims description 33
- 239000011248 coating agent Substances 0.000 claims description 30
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 29
- 229910002804 graphite Inorganic materials 0.000 claims description 24
- 239000010439 graphite Substances 0.000 claims description 24
- 238000000151 deposition Methods 0.000 claims description 15
- 230000008021 deposition Effects 0.000 claims description 13
- 238000001479 atomic absorption spectroscopy Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000003754 machining Methods 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 238000000197 pyrolysis Methods 0.000 claims description 3
- 239000010410 layer Substances 0.000 description 11
- 238000000034 method Methods 0.000 description 11
- 239000007789 gas Substances 0.000 description 8
- 238000007789 sealing Methods 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910021397 glassy carbon Inorganic materials 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052715 tantalum Inorganic materials 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/74—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited using flameless atomising, e.g. graphite furnaces
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
- C04B35/522—Graphite
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/01—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes on temporary substrates, e.g. substrates subsequently removed by etching
Description
【発明の詳細な説明】
本発明は無炎原子吸収分光分析（以下AASと
称する）用の熱分解グラフアイト（以下ピログラ
フアイトと称する）るつぼ若しくは管或いはキユ
ベツトに関するものである。本発明はまたピログ
ラフアイト被膜の堆積中生ずる熱膨張を考慮し、
所望のるつぼ形状および寸法に対応する形状およ
び寸法を有する高融点材料のスピンドル上に気相
からピログラフアイトの被膜を反応性堆積を行う
ことによりるつぼを製造する方法に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pyrolytic graphite (hereinafter referred to as pyrographite) crucible or tube or cuvette for flameless atomic absorption spectroscopy (hereinafter referred to as AAS). The present invention also takes into account the thermal expansion that occurs during the deposition of the pyrographite coating,
The present invention relates to a method of manufacturing a crucible by reactive deposition of a coating of pyrographite from the gas phase onto a spindle of high melting point material having a shape and dimensions corresponding to the desired crucible shape and dimensions.
AASるつぼは試料を分析するための容器およ
び加熱装置として使用される。特に管状体がるつ
ぼとして使用される（***特許出願第2006032号
および第2148777号）。これ等のるつぼは一般に耐
高温性で導電性の材料から成る。この理由は通常
分析すべき試料は直流通路でるつぼの抵抗加熱に
より加熱されるからである。他の加熱方法、例え
ば誘導加熱または輻射加熱方法が用いられること
も勿論である。 AAS crucibles are used as containers and heating devices for analyzing samples. In particular, tubular bodies are used as crucibles (German patent applications no. 2006032 and no. 2148777). These crucibles are generally made of high temperature resistant and electrically conductive materials. The reason for this is that the sample to be analyzed is usually heated in the DC path by resistive heating of the crucible. Of course, other heating methods can also be used, such as induction heating or radiant heating methods.
かかるるつぼ用の好ましい材料は炭素、特に分
光学的に純粋な電気グラフアイトの形態の炭素で
ある。 A preferred material for such a crucible is carbon, particularly in the form of spectrally pure electrographite.
AASにおいて常に使用されているグラフアイ
トるつぼに適当に配向したピログラフアイトの薄
い被膜を被着することにより予期されなかつた程
度に多数の元素に、特に有用な元素に対する検出
感度を改善することができ、即ち何回をるつぼを
使用することができるようになつた（英国ケンブ
リツジのパイ・ユニカム・リミテツドにより発行
された内容説明書「アトミツク・アブソープシヨ
ンウイズ・エレクトロサーマル・アトマイゼーシ
ヨン」）。余り維持管理を必要としない自動分析装
置において有効寿命が長いことはかなり重要であ
る。業界の現状で、通常の即ち末被覆グラフアイ
トるつぼは恐らくピログラフアイトで被覆された
ものに次第に置き換えられる。 By applying a thin coating of appropriately oriented pyrographite to the graphite crucibles commonly used in AAS, it has been possible to unexpectedly improve the detection sensitivity for a large number of elements, especially for useful elements. (Instructions for Atomic Absorption with Electrothermal Atomization published by Pai Unicom Limited, Cambridge, UK) . A long useful life is of considerable importance in automated analyzers that require little maintenance. With the current state of the industry, conventional or uncoated graphite crucibles are likely to be gradually replaced by those coated with pyrographite.
それにも拘らず形状および材料の異なる若干の
るつぼが使用され続けられている技術的および物
理化学的の多くの理由がある。主題に対する文
献、特に特許文献には、種々の形状（***特許出
願第2221184号）およびタンタルおよびタングス
テンのような種々の材料（前記「アトミツク・ア
ブソープシヨン・ウイズ・エレクトロサーマル・
アトマイゼーシヨン」）；ガラス質炭素（***特許
出願第2034960号）およびピログラフアイト（西
独特許出願第25549号）に対する多くの提案がな
されている。 There are many technical and physicochemical reasons why crucibles of different shapes and materials nevertheless continue to be used. The literature on the subject, in particular the patent literature, describes different geometries (West German Patent Application No. 2221184) and different materials such as tantalum and tungsten (see above)
A number of proposals have been made for glassy carbon (German patent application No. 2034960) and pyrographite (German patent application No. 25549).
現在ピログラフアイトだけから成るるつぼに対
する研究（例えばアナリテイカル・ケミストリー
44（1972）1718〜1720）は、ピログラフアイトで
単に被覆されたグラフアイトるつぼの場合と同様
の良好な結果、特に長い有効寿命が見出された証
拠を示していないことは若干意外と思われること
である。 Currently, research on crucibles made only of pyrographite (e.g. analytical chemistry)
44 (1972) 1718-1720) shows no evidence of similar good results, particularly a long useful life, as in the case of graphite crucibles simply coated with pyrographite. That's true.
本発明の目的はピログラフアイトのみから成る
るつぼの有効寿命を増すことにある。 The purpose of the invention is to increase the useful life of crucibles made solely of pyrographite.
本発明はこの目的を、外面の少くとも若干の部
分を機械加工したピログラフアイトの中空プレフ
オームから成るるつぼで、この中空プレフオーム
の内面および外面に少くとも１つの他のピログラ
フアイト被膜が被着されているるつぼにより達成
する。 The present invention addresses this objective with a crucible consisting of a hollow preform of pyrographite machined at least in part on its outer surface, the hollow preform having at least one other coating of pyrographite applied to its inner and outer surfaces. Achieved by a crucible that has been
本発明のるつぼを製造するのに使用する方法
は、気相からのピログラフアイトの反応性堆積に
おけるガス圧力、温度および堆積時間を、ピログ
ラフアイト被膜の厚さがるつぼの所望の外方寸法
と壁厚に相当するより僅かに大きくなるような方
法で制御し、このようにしてピログラフアイトで
つくられた中空基本体を、その外部表面を機械加
工することにより所望の外方寸法および壁厚に
し、このようにしてつくつた末被覆の粗製るつぼ
の内部表面および外部表面にピログラフアイトの
他の被膜を被着する前記反応性堆積によるのが好
ましい。 The method used to make the crucibles of the present invention involves adjusting the gas pressure, temperature and deposition time in the reactive deposition of pyrographite from the gas phase so that the thickness of the pyrographite coating is adjusted to the desired external dimensions of the crucible. The hollow basic body thus made of pyrographite can be shaped to the desired external dimensions and walls by machining its external surface in such a way that it is slightly larger than the corresponding wall thickness. Preferably, this is done by reactive deposition, in which the inner and outer surfaces of the powder-coated crude crucible thus produced are coated with another coating of pyrographite.
ピログラフアイトの絶対的特徴の一つは文献に
しばしば記載されているようにその物理的特徴に
おける顕著な異方性である。グラフアイト層格子
構造の密に充填された微小結晶の高度の配向によ
り表わされるこの異方性は化学的挙動にまでのび
る。生長の方向に平行に即ち実際には薄層の層形
成に垂直にとつたピログラフアイトの薄片を観察
すると、生長の方向に沿うかまたは対向する方向
に関して層はところどころで異なつているので不
均質であることがわかる。従つてこの不均質であ
ることに関連して層の性質が場所によつて若干変
化することが当然考えられる。 One of the absolute characteristics of pyrographite is the pronounced anisotropy in its physical characteristics, as often described in the literature. This anisotropy, expressed by the high degree of orientation of the closely packed microcrystals of the graphite layer lattice structure, extends to the chemical behavior. If we observe a slice of pyrographite taken parallel to the direction of growth, i.e. perpendicular to the layering of the thin layers, we find that the layers are heterogeneous because they differ in places along or opposite the direction of growth. It can be seen that it is. Therefore, it is natural that the properties of the layer may vary slightly depending on the location due to this non-uniformity.
本発明を達成する間に行つた一連の試験によ
り、例えばピログラフアイトの酸化速度は、試料
の、堆積法により自然に生長した外面がまたは支
持体に最初接触していた内面が酸素含有ガス（空
気）に曝されるかによつて著しく変化することが
わかつた。約700〜1000℃の範囲の制御した反応
温度において燃焼速度は、支持体側で燃焼が行わ
れる場合即ち層の生長方向と同じ方向では反対方
向の場合より1.6〜3.0倍大であることを見出し
た。被覆るつぼの場合従来良好である体験と一緒
にこの有意な知見により本発明のAASるつぼの
設計が導かれ、この製造法を以下に詳細に記載す
る。 A series of tests carried out while working on the present invention showed that the rate of oxidation of, for example, pyrographite was determined by the deposition method on the naturally grown outer surface of the sample or on the inner surface, which was initially in contact with the support, exposed to oxygen-containing gases. It was found that the temperature changes significantly depending on the exposure (air). It has been found that at controlled reaction temperatures in the range of approximately 700-1000°C, the combustion rate is 1.6-3.0 times greater when combustion takes place on the support side, i.e. in the same direction as the growth direction of the layer, than in the opposite direction. . This significant knowledge, together with the previously good experience with coated crucibles, led to the design of the AAS crucible of the present invention, the manufacturing method of which is described in detail below.
ピログラフアイトの被膜は支持体として作用す
る円筒形スピンドル上に気相から反応性堆積を使
用するそれ自体既知の方法（CVD法）により被
着され、上記支持体はタンタルの如き高融点物質
から成るが、電気グラフアイトまたはガラス質炭
素から成るのが好ましく、できるだけ最高に研摩
された表面を有する。使用する支持体スピンドル
の直径は、堆積温度（約2000℃）において起る熱
膨張を考慮し、製造すべきるつぼの内径に相当す
るような大きさである。一定の許容範囲内で、ガ
スの圧力および温度、特に堆積時間を介して制御
し得る堆積層の厚さは、るつぼの将来の外径より
幾分大なる値に調節する必要がある。被覆を完了
し、室温まで冷却した後、被覆を支持体からはず
すことができる。これにより平滑な内表面を有す
るピログラフアイトの中空円筒体が得られ、これ
を更に下記の如く加工して粗製るつぼを形成す
る。普通支持体スピンドルを再び使用して他の被
覆処理を行う。 The coating of pyrographite is applied by a method known per se using reactive deposition from the gas phase (CVD method) onto a cylindrical spindle acting as a support, said support being made of a high melting point material such as tantalum. It is preferably made of electrographite or vitreous carbon, and has a surface that is as highly polished as possible. The diameter of the support spindle used is such that it corresponds to the internal diameter of the crucible to be produced, taking into account the thermal expansion that occurs at the deposition temperature (approximately 2000° C.). Within certain tolerances, the thickness of the deposited layer, which can be controlled via the gas pressure and temperature, in particular the deposition time, must be adjusted to a value somewhat larger than the future outer diameter of the crucible. After coating is completed and cooled to room temperature, the coating can be removed from the support. This yields a hollow cylinder of pyrographite with a smooth inner surface, which is further processed to form a crude crucible as described below. The support spindle is usually used again for other coating operations.
得られた中空ピログラフアイト円筒を更に加工
して粗製るつぼを得る。これを切断するが、旋盤
上で硬質金属器具（切断のみ）またはダイヤモン
ドホイールを用いると最も良く一定の長さに切断
される。高速グラインダーを使用して所望の壁厚
に研摩するのが最もよい。通常るつぼの側部に１
個または２個以上の孔をつくることが必要であ
る。このことは研摩前普通のドリルを使用して行
うのが最も良い。これ等の機械加工を行つた後、
粗製るつぼを浄化し（例えば超音波浴で脱脂媒質
を使用し）、乾燥し、ピログラフアイト被覆所に
送る。 The obtained hollow pyrographite cylinder is further processed to obtain a crude crucible. This is best cut to length on a lathe using a hard metal tool (cutting only) or a diamond wheel. It is best to grind to the desired wall thickness using a high speed grinder. Usually 1 on the side of the crucible
It is necessary to make one or more holes. This is best done using a regular drill before sanding. After performing these machining processes,
The crude crucible is cleaned (for example using a degreasing medium in an ultrasonic bath), dried and sent to a pyrographite coating station.
上記の如く製造した粗製るつぼを既知方法で１
層以上の薄いピログラフアイト層で被覆する。こ
の工程を行う一つの方法は例えば***特許出願
P2825759。２−52に提案されている。この後被
覆は本発明の絶体必要とする特徴である。 The crude crucible produced as described above was prepared by a known method.
coated with a thin layer of pyrographite. One way to perform this process is, for example, by filing a West German patent application.
P2825759. Proposed in 2-52. This post-coating is an essential feature of the present invention.
支持体側部のるつぼの内面上のすべての反応性
中心を、穿孔、切断および研摩によりつくられた
末被覆の活性表面および中心と同様の方法で封鎖
する。このようにしてるつぼに、その品質と長い
有効寿命と一緒に引用した特許出願において提案
されたるつぼの化学的不動態を与える。 All reactive centers on the inner surface of the crucible on the sides of the support are sealed in a similar manner to the active surfaces and centers of the powder coating produced by drilling, cutting and polishing. This gives the crucible the chemical passivity of the crucible proposed in the cited patent application along with its quality and long useful life.
第２のまたは多数の後被覆によりもたらされる
この「封止」が、操作上およびるつぼの有効寿命
に対しマイナスの影響をともなう、ピログラフア
イト部分にしばしば存在する層間亀裂および欠陥
を封鎖する。 This "sealing" provided by the second or multiple post-coatings seals the interlayer cracks and defects that are often present in the pyrographite parts, with negative effects on the operational and useful life of the crucible.
この「封止」層は生長方向に相当するｃ−軸が
すべての場所でベース（粗製るつぼ）に垂直であ
るように配向させる。このことはまたるつぼの電
気抵抗が、電流に対する接点表面を形成する特に
環状終端領域で増すことを意味する。同じことが
接点表面における耐熱性に適合する。両方の作用
は、第１に加熱電力における好ましい電流／電圧
比のために、第２にるつぼから放出される熱を防
止するので、望ましいことである。 This "sealing" layer is oriented such that the c-axis, corresponding to the growth direction, is perpendicular to the base (crude crucible) in all places. This also means that the electrical resistance of the crucible increases, especially in the annular termination region, which forms the contact surface for the current. The same applies to the heat resistance on the contact surfaces. Both effects are desirable, firstly because of the favorable current/voltage ratio in the heating power and secondly because they prevent heat being released from the crucible.
「封止」層はまた他の機械的剛性を与える。従
つて尚十分に安定である極めて薄い壁のるつぼを
つくることが可能である。実際にフレーキングの
危険は取除かれる。 The "sealing" layer also provides other mechanical rigidity. It is therefore possible to create very thin-walled crucibles that are still sufficiently stable. Actually the risk of flaking is eliminated.
多数の支持体に被膜を同時に被着することがで
きる***特許第1667649号および第1667650号に開
示されている高温壁熱分解法を使用することは、
中空体を大量生産し次いで被覆するために最も好
ましい。均質性が同じであるように被覆を少くと
も２段階で実施すべきである。所望の被覆厚によ
り左右されるが、このことは少くとも封止処理に
適合し、一方プレフオームの製造における壁厚の
変化は、プレフオームをつくる場合壁厚が大きす
ぎる場合には、引続く機械加工により補償するこ
とができる。 Using the hot wall pyrolysis process disclosed in German Patent Nos. 1,667,649 and 1,667,650, which allows the simultaneous application of coatings to a large number of substrates,
Most preferred for mass production and subsequent coating of hollow bodies. The coating should be carried out in at least two stages so that the homogeneity is the same. Depending on the desired coating thickness, this is at least compatible with the sealing process, while variations in wall thickness during the manufacture of the preform may be affected by subsequent machining if the wall thickness is too large when making the preform. can be compensated by.
この方法は、単に正確に円筒形の支持体のみに
制限されるものではない。他の内部形状、例えば
円錐状に両端が拡がるかまたは段階的に拡がる形
状をつくることができる。必要であるすべてのも
のは、２つ以上の別個の部分の支持体コアを、好
ましくは心出しピンを用いてつくることである。
外被被覆から支持体部分を取除くことを不可能に
するアンダーカツトは回避する必要がある。 This method is not restricted to just precisely cylindrical supports. Other internal shapes can be made, such as conically flared at both ends or stepped flares. All that is required is to make the support core in two or more separate parts, preferably using centering pins.
Undercuts that make it impossible to remove the support portion from the overcoat should be avoided.
従つてAASるつぼは、それ自体既知であるよ
うに、ピログラフアイトだけでできているが、ピ
ログラフアイトプレフオームに再び封止被膜を被
着する。プレフオームの内部表面上の封止被膜の
生長方向は、プレフオームの内側のピログラフア
イトの生長方向と反対方向である。プレフオーム
の外部表面上の封止被膜はプレフオームの生長方
向と同じ方向に生長（エピタキシヤル生長）す
る。このことは支持体に面する表面の若干増した
化学的反応性を封ずるだけでなく、また殆んど常
に存在するかまたは操作中できる層間の亀裂およ
び欠陥を封鎖しこれにより任意の物質が内部に進
入するのが防止される。本発明のこの効果は、例
えば通常のグラフアイト管状るつぼの被覆（封
止）において、完全な薄いピログラフアイト被膜
により達成されたグラフアイトだけから成るるつ
ぼの従来の使用では、性質の改善が観察されなか
つた理由と考えられる。特に後者はるつぼの異状
に長い有効寿命に適合する。これ等の特徴の外に
本発明の多層被覆るつぼはまた電気的、熱的およ
び機械的利点を有する。 The AAS crucible is therefore, as is known per se, made entirely of pyrographite, but again applying a sealing coat to the pyrographite preform. The direction of growth of the sealing coating on the interior surface of the preform is opposite to the direction of growth of the pyrographite inside the preform. The sealing coating on the external surface of the preform grows in the same direction as the growth direction of the preform (epitaxial growth). This not only seals the slightly increased chemical reactivity of the surface facing the support, but also seals interlayer cracks and defects that are almost always present or created during operation, thereby preventing any material from being absorbed. Entry into the interior is prevented. This effect of the present invention has been demonstrated, for example, in the coating (sealing) of conventional graphite tubular crucibles, where the improvement in properties observed in conventional use of crucibles consisting solely of graphite was achieved with a completely thin pyrographite coating. This is thought to be the reason why it was not done. The latter in particular is compatible with the extraordinarily long useful life of the crucible. Besides these features, the multilayer coated crucible of the present invention also has electrical, thermal and mechanical advantages.
これに関して次の知見は注目すべきである：ピ
ログラフアイトを、更に被覆するための支持体と
して使用する場合には、新しい被膜が支持体（ピ
ログラフアイトの）外部の自然に得られた最終表
面にエピタキシヤル生成し、即ち結晶構造が維持
され、一般に分離線は検出されない。この法則
は、この一表面が物理的、科学的または機械的い
ずれかの任意の方法により変えられない限り、こ
の一表面だけに適合される。個々の被覆工程の間
の任意のガス吸収は無意味のことである。この理
由はガスが、次の被覆処理中、即ち吸入排出およ
び強力加熱工程において、実際に再びすべて脱着
されるからである。 The following finding is noteworthy in this regard: When pyrographite is used as a support for further coating, a new coating is formed on the surface of the naturally obtained final layer on the outside of the support (of the pyrographite). Epitaxial formation occurs on the surface, ie the crystal structure is maintained, and generally no separation lines are detected. This law applies only to this one surface unless this surface is altered by any method, either physical, scientific or mechanical. Any gas absorption during the individual coating steps is of no significance. The reason for this is that the gases are virtually all desorbed again during the subsequent coating process, ie during the suction discharge and intensive heating steps.
新しい層がすべての他の表面上に、特に最初支
持体上に結合した内部表面上に普通エピタキシヤ
ルでなく生長する。 New layers are usually grown non-epitaxially on all other surfaces, especially on the internal surfaces that were originally bonded to the support.
次に本発明を図面を参照して実施例につき説明
する。 Next, the invention will be explained by way of example with reference to the drawings.
添付図面は水平操作するAASるつぼの断面図
である。このるつぼはピログラフアイトの外被被
膜２で被覆されたピログラフアイトのプレフオー
ム１からなる。るつぼはその両端に接点表面３を
有する。るつぼの壁における貫通した孔４を用い
て分析すべき物質５を挿入する。るつぼを使用し
ている場合測定ビームは線６−６に沿つて通過す
る。 The accompanying drawing is a cross-sectional view of a horizontally operated AAS crucible. The crucible consists of a pyrographite preform 1 coated with an outer coating 2 of pyrographite. The crucible has contact surfaces 3 at both ends thereof. A through hole 4 in the wall of the crucible is used to insert the substance 5 to be analyzed. When using a crucible, the measuring beam passes along line 6-6.
実施例 １
プロパンの雰囲気中、全圧ｐ＝2.3ミリバール、
温度2000℃で高温壁熱分解法を使用し、直径6.1
mmの研摩した表面を有する円筒グラフアイトスピ
ンドル上に堆積を行つた。室温まで冷却処理を行
つた際支持体スピンドルから次の寸法：
長さ ｌ＝６cm
外径 7.4mm
内径 6.2mm
平均壁厚さ δ＝600μｍ
を有するピログラフアイト円筒を引きぬくことが
できた。Example 1 In a propane atmosphere, total pressure p = 2.3 mbar,
Using high temperature wall pyrolysis method at temperature 2000℃, diameter 6.1
Deposition was carried out on a cylindrical graphite spindle with a polished surface of mm. After cooling to room temperature, it was possible to draw out a pyrographite cylinder having the following dimensions from the support spindle: length l=6 cm, outer diameter 7.4 mm, inner diameter 6.2 mm, average wall thickness δ=600 μm.
このピログラフアイトの性質は次の通りであつ
た：
比重 γ＝2.1ｇcm-3
長さｌに亘る抵抗 0.1Ω以下
比抵抗 10-3Ω・cm以下
軸荷重における
極限引張応力（σ）：軸荷重における極限引張力
は52Kgｆ〔＝510N、但し１Kgｆ＝9.8N〕以上、
従つてσ406Kgｆ／cm2（3979N／cm2）
実施例 ２
40個のグラフアイトの支持体スピンドル（電気
グラフアイト）を実施例１に示した条件で同様に
被覆し、同様にして40個のピログラフアイト円筒
を製造した。これ等の円筒を旋盤で加工すること
により長さを2.8cmに減じた。次いで直径1.5mmの
孔を円筒の側壁の中心にあけた。これ等の外径
7.4mmおよび内径6.2mmの粗製るつぼの外部表面
を、グラインダーで加工し、壁厚を0.5〜0.1mmの
範囲とし、即ち外径6.4〜7.2mmの範囲とした。こ
のようにしてつくつた粗製るつぼの厚さを有する
封止ピログラフアイト被覆を被着した。 The properties of this pyrographite were as follows: Specific gravity γ = 2.1 g cm -3 Resistance over length 1 0.1 Ω or less Specific resistance 10 -3 Ω cm or less Ultimate tensile stress (σ) under axial load: Axial The ultimate tensile force under load is 52Kgf [=510N, however, 1Kgf=9.8N] or more,
Therefore, σ406Kgf/cm 2 (3979N/cm 2 ) Example 2 40 graphite support spindles (electrographite) were similarly coated under the conditions shown in Example 1, and 40 pyrographite were coated in the same manner. A graphite cylinder was manufactured. By machining these cylinders on a lathe, the length was reduced to 2.8 cm. A hole with a diameter of 1.5 mm was then drilled in the center of the side wall of the cylinder. These outer diameters
The external surface of a 7.4 mm and 6.2 mm internal diameter crude crucible was machined with a grinder to give a wall thickness in the range 0.5 to 0.1 mm, ie an external diameter in the range 6.4 to 7.2 mm. A sealed pyrographite coating having the thickness of the crude crucible thus produced was applied.
添付図面は水平操作するAASるつぼの断面図
である。
１……プレフオーム、２……外被被覆、３……
接点表面、４……孔、５……分析すべき物質。
The accompanying drawing is a cross-sectional view of a horizontally operated AAS crucible. 1...Preform, 2...Outer covering, 3...
Contact surface, 4...hole, 5...substance to be analyzed.
Claims (1)
るつぼにおいて、るつぼがその外面の少くとも若
干の部分を機械加工した熱分解グラフアイトの中
空プレフオーム１からなり、この中空プレフオー
ムの外面および内面に少くとも１層の他の熱分解
グラフアイトの被膜２が被着されていることを特
徴とする熱分解グラフアイトるつぼ。 ２ 外面の少くとも若干の部分を機械加工した熱
分解グフアイトの中空プレフオームの外面および
内面に少くとも１層の他の熱分解グフアイトの被
膜を被着して成る無炎原子吸収分光分析用熱分解
グラフアイトるつぼを製造するに当り、熱分解グ
ラフアイト被膜の堆積中生ずる熱膨張を考慮し、
所望のるつぼの形状および寸法に対応する形状お
よび寸法を有する高融点材料のスピンドル上に気
相から熱分解グラフアイトの被膜を反応性堆積を
行い、熱分解グラフアイトの反応性堆積を行う間
ガスの圧力および温度並びに堆積時間を熱分解グ
ラフアイトの被膜の厚さがるつぼの所望の外方寸
法と壁厚に必要であるより僅かに大きくなるよう
な方法で制御し、このようにしてつくられた中空
熱分解グラフアイトのプレフオームを、その外部
表面を機械加工することにより所望の外側寸法お
よび壁厚にし、このようにして得た未被覆の粗製
るつぼの内部表面及び外部表面上に熱分解グラフ
アイトの他の少くとも１層の被膜を被着すること
を特徴とする熱分解グラフアイトるつぼの製造方
法。[Scope of Claims] 1. A pyrolytic graphite crucible for flameless atomic absorption spectroscopy, wherein the crucible consists of a hollow preform 1 of pyrolytic graphite with at least a part of its outer surface machined, A pyrolytic graphite crucible characterized in that at least one other coating 2 of pyrolytic graphite is applied to the outer and inner surfaces. 2 Pyrolysis for flameless atomic absorption spectroscopy, comprising a hollow preform of pyrolytic guhuaite with at least a portion of the outer surface machined, and at least one other coating of pyrolytic guhuaite coated on the outer and inner surfaces of the hollow preform. In manufacturing the graphite crucible, we take into account the thermal expansion that occurs during the deposition of the pyrolytic graphite coating.
Reactive deposition of a coating of pyrolytic graphite from the gas phase onto a spindle of a high melting point material having a shape and dimensions corresponding to the shape and dimensions of the desired crucible, and during the reactive deposition of pyrolytic graphite, the gas The pressure and temperature of the pyrolytic graphite and the deposition time are controlled in such a way that the thickness of the coating of pyrolytic graphite is slightly greater than that required for the desired external dimensions and wall thickness of the crucible, and the A preform of hollow pyrolytic graphite is given the desired external dimensions and wall thickness by machining its external surface, and a pyrolytic graphite is formed on the internal and external surfaces of the uncoated crude crucible thus obtained. 1. A method for producing a pyrolytic graphite crucible, which comprises depositing at least one other layer of graphite.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792949275 DE2949275A1 (en) | 1979-12-07 | 1979-12-07 | CUEVETTE FOR THE FLAMELESS ATOMIC ABSORPTION SPECTROSCOPY AND METHOD FOR THE PRODUCTION THEREOF |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5692434A JPS5692434A (en) | 1981-07-27 |
| JPS6333660B2 true JPS6333660B2 (en) | 1988-07-06 |
Family
ID=6087845
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17033880A Granted JPS5692434A (en) | 1979-12-07 | 1980-12-04 | Thermally cracked graphite grucible and producing same |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5692434A (en) |
| DE (1) | DE2949275A1 (en) |
| FR (1) | FR2471599B1 (en) |
| GB (1) | GB2064500B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3208247A1 (en) * | 1982-03-08 | 1983-09-22 | Philips Patentverwaltung Gmbh, 2000 Hamburg | CUVETTE FOR THE ATOMIC ABSORPTION SPECTROMETRY |
| DE3208744A1 (en) * | 1982-03-11 | 1983-09-22 | Philips Patentverwaltung Gmbh, 2000 Hamburg | TUBE COVETTE FOR THE ATOMIC ABSORPTION SPECTROMETRY |
| DE3239253A1 (en) * | 1982-10-23 | 1984-04-26 | Philips Patentverwaltung Gmbh, 2000 Hamburg | TUBE COVETTE FOR THE ATOMIC ABSORPTION SPECTROMETRY |
| GB2144871A (en) * | 1983-08-03 | 1985-03-13 | Philips Electronic Associated | Tube cell for atomic absorption spectrophotometry |
| DE3720376A1 (en) * | 1987-06-19 | 1988-12-29 | Bodenseewerk Perkin Elmer Co | OVEN FOR ELECTROTHERMAL ATOMIZATION FOR THE ATOMIC ABSORPTION SPECTROSCOPY |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53121677A (en) * | 1977-01-20 | 1978-10-24 | Philips Nv | Cuvettes |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3411123A (en) * | 1966-05-10 | 1968-11-12 | Gen Electric | Pyrolytic graphite electrical resistance element |
| DE2450261C3 (en) * | 1974-10-23 | 1980-06-26 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Process for the production of grid electrodes for electron tubes |
-
1979
- 1979-12-07 DE DE19792949275 patent/DE2949275A1/en not_active Ceased
-
1980
- 1980-12-01 FR FR8025453A patent/FR2471599B1/fr not_active Expired
- 1980-12-03 GB GB8038729A patent/GB2064500B/en not_active Expired
- 1980-12-04 JP JP17033880A patent/JPS5692434A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53121677A (en) * | 1977-01-20 | 1978-10-24 | Philips Nv | Cuvettes |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5692434A (en) | 1981-07-27 |
| DE2949275A1 (en) | 1981-06-25 |
| GB2064500A (en) | 1981-06-17 |
| FR2471599A1 (en) | 1981-06-19 |
| FR2471599B1 (en) | 1983-12-16 |
| GB2064500B (en) | 1983-06-08 |
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