TWI716526B

TWI716526B - Nickel powder

Info

Publication number: TWI716526B
Application number: TW106100782A
Authority: TW
Inventors: 大栗雅人; 淺井剛; 吉田貢
Original assignee: 日商東邦鈦股份有限公司
Priority date: 2016-01-12
Filing date: 2017-01-11
Publication date: 2021-01-21
Also published as: CN108430673B; JPWO2017122689A1; WO2017122689A1; KR102589697B1; JP6876001B2; CN108430673A; KR20180101504A; TW201736617A

Abstract

提供一種鎳粉末，其能顯示優異的燒結行為和分散性，其結果，能防止脫層而適合導電膏用。一種鎳粉末，其具有包含氧化鎳及氫氧化鎳的被膜，平均粒徑為250nm以下，在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p3/2整體光譜的面積比為55.0~80.0%，金屬鎳的波峰對Ni2p3/2整體光譜的面積比為5.0~15.0%，歸屬於鎳和氫氧基的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為5.0~40.0%，前述被膜的厚度平均為3.0~5.0nm。 Provided is a nickel powder which can exhibit excellent sintering behavior and dispersibility, and as a result, can prevent delamination and is suitable for conductive paste. A nickel powder having a coating film containing nickel oxide and nickel hydroxide, with an average particle size of 250 nm or less, which is attributed to the analysis of the chemical bonding state of nickel in the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS) The area ratio of the peak of the bonding state of nickel and oxygen to the overall spectrum of Ni2p3/2 is 55.0~80.0%, and the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p3/2 is 5.0~15.0%, which is attributed to nickel and hydroxide. The area ratio of the peak of the bonded state to the overall spectrum of Ni2p _3/2 is 5.0-40.0%, and the thickness of the aforementioned film is 3.0-5.0nm on average.

Description

鎳粉末 Nickel powder

本發明係關於適合用於導電膏用的鎳粉末，特別是關於積層陶瓷電容器的內部電極中所使用的燒結特性及分散性優異的鎳粉末。 The present invention relates to nickel powders suitable for use in conductive pastes, and particularly to nickel powders having excellent sintering characteristics and dispersibility used in internal electrodes of multilayer ceramic capacitors.

目前，銀、鈀、鉑、金等的貴金屬粉末，或者是鎳、鈷、鐵、鉬、鎢等的卑金屬粉末係用作作為電子材料用的導電膏，特別是積層陶瓷電容器的內部電極用。一般而言，積層陶瓷電容器成為下述結構：交替重疊介電體陶瓷層、和用作內部電極的金屬層，在介電體陶瓷層的兩端，連接有與內部電極的金屬層連接的外部電極。此處，作為構成介電體的材料，可使用以鈦酸鋇、鈦酸鍶、氧化釔等的介電率高的材料作為主要成分者。另一方面，作為構成內部電極的金屬，可使用前述的貴金屬粉末或卑金屬粉末，但最近要求更便宜的電子材料，因此積極地進行利用後者的卑金屬粉末的積層陶瓷電容器的開發，特別是以金屬鎳粉末為代表。 At present, noble metal powders such as silver, palladium, platinum, gold, or base metal powders such as nickel, cobalt, iron, molybdenum, and tungsten are used as conductive pastes for electronic materials, especially for internal electrodes of multilayer ceramic capacitors. . In general, a multilayer ceramic capacitor has a structure in which a dielectric ceramic layer and a metal layer used as an internal electrode are alternately overlapped, and the two ends of the dielectric ceramic layer are connected to the outside connected to the metal layer of the internal electrode. electrode. Here, as a material constituting the dielectric body, a material having a high dielectric constant such as barium titanate, strontium titanate, and yttrium oxide can be used as a main component. On the other hand, as the metal constituting the internal electrode, the aforementioned noble metal powder or base metal powder can be used. Recently, cheaper electronic materials are required. Therefore, the development of multilayer ceramic capacitors using the latter base metal powder is actively carried out, especially It is represented by metallic nickel powder.

然而，使用金屬鎳粉末作為內部電極的積層陶瓷電容器一般是用以下的方法製造。即，將鈦酸鋇等的介電體粉末與有機黏結劑混合並使其懸浮，利用刮刀法將其成形為薄片狀而作成介電體胚片。另一方面，將內部電極用的金屬鎳粉末與有機溶劑、塑化劑、有機黏結劑等的有機化合物混合而形成金屬鎳粉末膏，用網版印刷法將其印刷在前述胚片上。接著，進行乾燥、積層及壓接，利用加熱處理除去有機成分後，在氫氣的還原性氣體環境下進一步升溫而在1000~1300℃或其以上的溫度下進行燒成，之後，在介電體陶瓷層的兩端燒接外部電極，得到積層陶瓷電容器。 However, multilayer ceramic capacitors using metallic nickel powder as internal electrodes are generally manufactured by the following method. That is, barium titanate, etc. The dielectric powder is mixed with an organic binder and suspended, and it is formed into a thin sheet by a doctor blade method to make a dielectric green sheet. On the other hand, metallic nickel powder for internal electrodes is mixed with organic compounds such as organic solvents, plasticizers, organic binders, etc. to form metallic nickel powder paste, which is printed on the green sheet by screen printing. Next, drying, lamination, and pressure bonding are performed. After the organic components are removed by heat treatment, the temperature is further increased in a reducing gas atmosphere of hydrogen and fired at a temperature of 1000 to 1300°C or higher. After that, the dielectric Both ends of the ceramic layer are fired with external electrodes to obtain a multilayer ceramic capacitor.

在如上述的積層陶瓷電容器的製造方法中，將金屬膏印刷在介電體胚片，進行積層及壓接後，利用加熱處理蒸發除去有機成分的加熱處理係通常在大氣中、在250~400℃下進行。依此方式在氧化氣體環境中進行加熱處理，因此金屬鎳粉末被氧化，因此引起體積的膨脹。同時，金屬鎳粉末開始燒結而開始引起體積的收縮。 In the manufacturing method of the multilayer ceramic capacitor as described above, the metal paste is printed on the dielectric green sheet, and after lamination and pressure bonding, the heat treatment system for evaporating and removing organic components by heat treatment is usually in the air at 250 to 400 Performed at ℃. In this way, the heat treatment is performed in an oxidizing gas environment, so the metal nickel powder is oxidized, thereby causing volume expansion. At the same time, the metallic nickel powder begins to sinter and begins to cause volume shrinkage.

依此方式，在製造積層陶瓷電容器的步驟中，因從300℃附近的低溫領域起的氧化還原-燒結反應，金屬鎳粉末中產生膨脹-收縮所造成的體積變化。此時，若在低溫階段金屬鎳粉末的氧化行為或燒結行為不穩定，則介電體層和電極層中容易產生應變，其結果，有引起龜裂或剝離等的被稱為脫層(delamination)的層狀構造的破壞這樣的問題。 In this way, in the step of manufacturing the multilayer ceramic capacitor, due to the oxidation-reduction-sintering reaction from the low temperature range around 300°C, the metal nickel powder undergoes a volume change due to expansion and contraction. At this time, if the oxidation behavior or sintering behavior of the metallic nickel powder is unstable in the low temperature stage, strain is likely to occur in the dielectric layer and the electrode layer. As a result, cracks or peeling are caused, which is called delamination The destruction of the layered structure is such a problem.

有人提出了各種方法作為解決如上述的脫層問題的手段。例如，日本特開平8-246001號公報中，公開一種相對於特定粒徑的振實密度(tap density)具有某極限值以上的金屬鎳粉末，記載：當藉由使用這樣的金屬鎳粉末來燒成膏中所分散的鎳粉末和介電體以製成電容器時，很難引起脫層。 Various methods have been proposed as a means to solve the delamination problem as described above. For example, in Japanese Patent Application Publication No. 8-246001, the A type of metallic nickel powder with a tap density of a specific particle size above a certain limit value is described, and it is recorded that when such metallic nickel powder is used to sinter the dispersed nickel powder and dielectric in the paste When making a capacitor, it is difficult to cause delamination.

然而，上述公報中，在改善燒結行為的目的方面提高了相應的效果，但在防止脫層的方法方面則未必是充分的，期盼有進一步改善。 However, in the above-mentioned publication, the corresponding effect is improved in terms of the purpose of improving the sintering behavior, but the method of preventing delamination is not necessarily sufficient, and further improvement is expected.

此外，日本特開2000-045001號公報、日本特開2000-045002號公報、國際公開WO2004/020128號公報中，公開能防止脫層的鎳粉末。具體而言，藉由在氧化性氣體環境下、在200~400℃、加熱處理時間為1分鐘~10小時下進行熱處理所得到的鎳粉末。 In addition, Japanese Patent Application Publication No. 2000-045001, Japanese Patent Application Publication No. 2000-045002, and International Publication No. WO2004/020128 disclose nickel powder that can prevent delamination. Specifically, it is a nickel powder obtained by heat-treating in an oxidizing gas environment at 200 to 400°C for a heat treatment time of 1 minute to 10 hours.

然而，此方法，在比250nm細的粒徑中產生急遽的氧化，含氧量增大，鎳粉末的凝集增加。因此，在還原氣體環境中進行燒成之際，鎳粉氧化物的還原所造成的氣體產生和體積變化變大，因此產生了下述問題：變得無法得到緻密的電極膜，同時引起積層電子零件的龜裂、脫層的問題、與共同材料(co-material)的混合因凝集的鎳粉末而變得不充分，引起脫層的問題。 However, in this method, rapid oxidation occurs in a particle size finer than 250 nm, the oxygen content increases, and the aggregation of nickel powder increases. Therefore, when firing in a reducing gas atmosphere, the gas generation and volume change caused by the reduction of nickel powder oxides become larger, which causes the following problem: it becomes impossible to obtain a dense electrode film, and at the same time, build-up electrons are caused. The problems of cracks and delamination of parts, and the mixing with co-materials are insufficient due to the agglomerated nickel powder, causing delamination problems.

由此，本發明有鑑於上述先前技術的問題點，目的在於在積層陶瓷電容器的製造步驟中所使用的平均粒徑250nm以下的鎳粉末方面，提供一種鎳粉末，其能顯示優異的燒結行為和分散性，其結果，能防止脫層而適合導電膏用。更具體而言，目的在於提供：在進行加熱處理之際，氧化還原反應所造成的體積變化或重量變化少，進一步地，燒結開始溫度比習知鎳粉末還高，更接近在製造積層陶瓷電容器之際使用的介電體的燒結開始溫度，其結果，能防止脫層的導電膏用鎳粉末。 Therefore, in view of the above-mentioned problems of the prior art, the present invention aims to provide nickel powder with an average particle diameter of 250 nm or less used in the manufacturing step of multilayer ceramic capacitors, which can exhibit excellent sintering behavior and Dispersibility, as a result, can prevent delamination and is suitable for conductive paste. More specifically, the purpose is to provide: the volume change or weight caused by the oxidation-reduction reaction during the heat treatment The change is small. Furthermore, the sintering start temperature is higher than that of conventional nickel powder, and is closer to the sintering start temperature of the dielectric body used in the manufacture of multilayer ceramic capacitors. As a result, the nickel powder for conductive paste can prevent delamination.

如前所述，在製造積層陶瓷電容器的步驟中，因氧化還原反應，鎳粉末中產生膨脹-收縮所造成的體積變化，由此產生了脫層。由此，若在鎳粉末的表面緻密地形成有厚的氧化被膜的話，便可抑制氧化從鎳粉末表面朝內部進行。 As described above, in the step of manufacturing a multilayer ceramic capacitor, the nickel powder undergoes a volume change due to expansion and contraction due to an oxidation-reduction reaction, thereby causing delamination. Therefore, if a thick oxide film is densely formed on the surface of the nickel powder, it is possible to prevent oxidation from proceeding from the surface of the nickel powder to the inside.

因此，本發明人等，針對金屬鎳粉末反覆進行深入研究，結果發現：在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，燒結行為依歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜波峰的面積比而改變，利用特定的方法所製造、具有特定的氧化被膜的金屬鎳粉末係燒結特性優異，因而完成本發明。 Therefore, the inventors of the present invention conducted intensive studies on metallic nickel powder and found that in the analysis of the chemical bonding state of nickel on the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS), the sintering behavior depends on nickel and The area ratio of the peak of the oxygen bonding state to the peak of the entire spectrum of Ni2p _3/2 is changed, and the metal nickel powder system produced by a specific method and having a specific oxide film is excellent in sintering characteristics, thus completing the present invention.

即，本發明的鎳粉末的特徵為：具有包含氧化鎳及氫氧化鎳的被膜，平均粒徑為250nm以下，在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為55.0~80.0%，金屬鎳的波峰對Ni2p_3/2整體光譜的面積比為5.0~15.0%，歸屬於鎳和氫氧基的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為5.0~40.0%，前述被膜的厚度平均為3.0~5.0nm。 That is, the nickel powder of the present invention is characterized by having a film containing nickel oxide and nickel hydroxide, an average particle diameter of 250 nm or less, and the chemical bonding state of nickel on the surface layer of the nickel powder based on X-ray photoelectron spectroscopy (XPS) In the analysis, the area ratio of the peak attributable to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 is 55.0~80.0%, and the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 is 5.0~15.0% , The area ratio of the peak attributable to the bonding state of nickel and hydroxyl groups to the overall spectrum of Ni2p _3/2 is 5.0 to 40.0%, and the thickness of the aforementioned coating is 3.0 to 5.0 nm on average.

根據本發明的鎳粉末，便能提供一種鎳粉末，其能顯示優異的燒結行為和分散性，其結果，能防止脫層而適合導電膏用。 According to the nickel powder of the present invention, a nickel powder can be provided , It can show excellent sintering behavior and dispersibility. As a result, it can prevent delamination and is suitable for conductive paste.

圖1係顯示在本發明的實施例1、比較例1、比較例2及比較例3所得到的鎳粉末的燒結行為的圖表。 FIG. 1 is a graph showing the sintering behavior of nickel powders obtained in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention.

[實施發明之形態] [The form of implementing the invention]

本發明的鎳粉末的個數平均粒徑為250nm以下。更佳為30~250nm，若為50~250nm範圍的微粒的話則更佳，若為140~250nm範圍的微粒的話則更合適。又，本發明的鎳粉末的平均粒徑係利用掃描電子顯微鏡拍攝鎳粉末的一次粒子的照片，由該照片使用影像解析軟體，測定500個以上粒子的粒徑，由所得到的鎳粉末的粒度分布算出其個數平均粒徑。此時，粒徑係包入粒子的最小圓的直徑。 The number average particle size of the nickel powder of the present invention is 250 nm or less. It is more preferably 30 to 250 nm, even more preferably in the range of 50 to 250 nm, and more suitable in the range of 140 to 250 nm. In addition, the average particle size of the nickel powder of the present invention is a photograph of the primary particles of the nickel powder taken with a scanning electron microscope. From the photograph, the particle size of 500 or more particles is measured using image analysis software. The particle size of the obtained nickel powder Calculate the number average particle size of the distribution. At this time, the particle size is the diameter of the smallest circle that encloses the particles.

此外，本發明的鎳粉末的個數平均粒徑D和比表面積徑d的比(d/D)較佳為0.7以上。本發明的比表面積徑係指將粒子假設為正球而由鎳微粉的比表面積計算。若d/D為0.7以上的話，便容易得到良好的膏，藉由塗布膏所得到的膜的膜密度變佳，在MLCC的製造步驟中，達到良好的燒結性。 In addition, the ratio (d/D) of the number average particle diameter D to the specific surface area diameter d of the nickel powder of the present invention is preferably 0.7 or more. The specific surface area diameter in the present invention is calculated from the specific surface area of the nickel fine powder assuming that the particles are true spheres. If d/D is 0.7 or more, it is easy to obtain a good paste, the film density of the film obtained by applying the paste becomes better, and good sinterability is achieved in the MLCC manufacturing process.

此外，鎳粉末的基於BET的比表面積較佳為2~30m²/g。 In addition, the BET-based specific surface area of the nickel powder is preferably 2 to 30 m ² /g.

另外，本發明的鎳粉末的粒子形狀為球狀，使得燒結特性或分散性提升，因而是理想的。本發明的球狀係指高寬比為1.2以下，圓形度係數為0.675以上。高寬比係包入粒子的最小橢圓的長徑和短徑的比。此外，圓形度係數係指當將包圍粒子的最小橢圓的面積設為S，將周圍長度設為L時，用4πS/(L×L)所定義的值。此外，藉由鎳粉末的形狀為球狀，在對MLCC的內部電極進行加工之際填充率變高，並且平坦性變佳，能夠抑制龜裂和脫層。 In addition, the particle shape of the nickel powder of the present invention is spherical, It is ideal to improve sintering characteristics or dispersibility. The spherical shape of the present invention means that the aspect ratio is 1.2 or less, and the circularity coefficient is 0.675 or more. The aspect ratio is the ratio of the major axis to the minor axis of the smallest ellipse that encloses the particle. In addition, the circularity coefficient refers to a value defined by 4πS/(L×L) when the area of the smallest ellipse surrounding the particle is S and the surrounding length is L. In addition, since the shape of the nickel powder is spherical, the filling rate is increased when the internal electrode of the MLCC is processed, and the flatness is improved, and cracking and delamination can be suppressed.

本發明的鎳粉末，係在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為55.0~80.0%，金屬鎳的波峰對Ni2p_3/2整體光譜的面積比為5.0~15.0%，歸屬於鎳和氫氧基的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為5.0~40.0%。換言之，具有在本發明的鎳粉末的表面所形成的包含氧化鎳及氫氧化鎳的被膜。此被膜的厚度平均為3.0~5.0nm。 The nickel powder of the present invention is based on the X-ray photoelectron spectroscopy (XPS) analysis of the chemical bonding state of nickel on the surface layer of the nickel powder. The peak attributable to the bonding state of nickel and oxygen vs. Ni2p _3/2 overall spectrum The area ratio of the metal nickel is 55.0~80.0%, and the area ratio of the metal nickel peak to the overall spectrum of Ni2p _3/2 is 5.0~15.0%. The peak attributable to the bonding state of nickel and the hydroxyl group has an impact on the overall spectrum of Ni2p _3/2 . The area ratio is 5.0~40.0%. In other words, it has a film containing nickel oxide and nickel hydroxide formed on the surface of the nickel powder of the present invention. The thickness of the film is 3.0 to 5.0 nm on average.

另外，本發明的鎳粉末，若進行紅外線吸收光譜分析，則具有肇因於與金屬鎳化學鍵結的OH基的波數為3600~3700cm^-1的吸收波峰者。 In addition, the nickel powder of the present invention, when subjected to infrared absorption spectroscopy, has an absorption peak of 3600 to 3700 cm ^-1 due to the OH group chemically bonded to metallic nickel.

依此方式形成有特定厚度的緻密的氧化鎳及氫氧化鎳被膜，從而可以在進行加熱處理之際，特別是，在積層陶瓷電容器的製造步驟中、在供除去有機成分用的300~400℃的溫度區域下受到加熱之際，減少鎳的氧化還原所造成的體積及重量的變化。 In this way, a dense nickel oxide and nickel hydroxide film of a specific thickness is formed, so that it can be heated at 300 to 400°C for the removal of organic components in the manufacturing process of multilayer ceramic capacitors. When heated in a temperature range of, it reduces the change in volume and weight caused by nickel oxidation and reduction.

本發明的鎳粉末係表面具有牢固的氧化鎳及氫氧化鎳被膜，因此燒結開始溫度比習知鎳粉末還高，更接近在製造積層陶瓷電容器之際使用的介電體的燒結開始溫度。由此，本發明的鎳粉末，加熱時的氧化行為或燒結行為比習知鎳粉末優異，因此能有效地防止脫層。 The surface of the nickel powder of the present invention has strong nickel oxide and The nickel hydroxide film has a higher sintering start temperature than conventional nickel powder, and is closer to the sintering start temperature of the dielectric used in the manufacture of multilayer ceramic capacitors. Thus, the nickel powder of the present invention has better oxidation behavior or sintering behavior during heating than conventional nickel powder, and therefore can effectively prevent delamination.

此外，本發明的鎳粉末係在純水等溶媒中的分散性佳。 In addition, the nickel powder of the present invention has good dispersibility in a solvent such as pure water.

本發明的Ni2p_3/2整體光譜係指在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，肇因於歸屬於金屬鎳的波峰、歸屬於鎳和氧的鍵結狀態的波峰及歸屬於鎳和氫氧基的鍵結狀態的波峰的光譜。各光譜的面積比係將所得到的Ni2p_3/2光譜進行波峰分離，算出各光譜的面積，求出各光譜對其總和的面積比例。 The Ni2p _3/2 overall spectrum of the present invention refers to the analysis of the chemical bonding state of nickel on the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS), which is caused by the peak attributable to metallic nickel, attributable to nickel and The spectrum of the peak of the bonding state of oxygen and the peak of the bonding state of nickel and hydroxyl groups. The area ratio of each spectrum is the peak separation of the obtained Ni2p _3/2 spectrum, the area of each spectrum is calculated, and the area ratio of each spectrum to the total is calculated.

本發明的被膜厚度，係利用穿透型電子顯微鏡觀察鎳粉末試料的晶格影像，將鎳粉末表面的被膜厚度進行6點測定，求出其平均者。 The film thickness of the present invention is obtained by observing the lattice image of the nickel powder sample with a transmission electron microscope, and measuring the film thickness on the surface of the nickel powder at 6 points to obtain the average.

更佳為，在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為60.0~75.0%，金屬鎳的波峰對Ni2p_3/2整體光譜的面積比為7.0~13.0%，歸屬於鎳和氫氧基的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為12.0~33.0%，氧化鎳及氫氧化鎳被膜的厚度平均為3.5~4.5nm。 More preferably, in the analysis of the chemical bonding state of nickel in the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS), the area ratio of the peak attributable to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 Is 60.0~75.0%, the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 is 7.0~13.0%, and the area ratio of the peak attributable to the bonding state of nickel and hydroxide to the overall spectrum of Ni2p _3/2 is 12.0~33.0%, the average thickness of nickel oxide and nickel hydroxide film is 3.5~4.5nm.

[鎳粉末的製造方法] [Method for manufacturing nickel powder]

本發明的鎳粉末能夠用例如氣相法、液相法等已知的方法製造。特別是，在能容易地控制生成的金屬微粉末的粒徑，進而能效率良好地製造球狀的粒子的方面上，較佳為藉由使氯化鎳氣體與還原性氣體接觸來生成鎳粉末的氣相還原法、或將熱分解性鎳化合物噴霧以進行熱分解的噴霧熱分解法。特別是，從能精密地控制生成的鎳粉末的粒徑，進而能防止粗大粒子的產生的方面出發，較佳為基於使氯化鎳氣體與還原性氣體接觸的氣相還原法。 The nickel powder of the present invention can be known by, for example, gas phase method, liquid phase method, etc. Method of manufacturing. In particular, it is preferable to produce nickel powder by contacting nickel chloride gas with a reducing gas in terms of easily controlling the particle size of the produced metal fine powder and thereby efficiently producing spherical particles. The gas-phase reduction method or the spray thermal decomposition method in which the thermally decomposable nickel compound is sprayed for thermal decomposition. In particular, since the particle size of the nickel powder to be produced can be precisely controlled and the generation of coarse particles can be prevented, a gas phase reduction method based on contacting nickel chloride gas with a reducing gas is preferable.

在氣相還原法中，使氣化的氯化鎳的氣體與氫等還原性氣體反應。在此情況下，也可以將固體的氯化鎳加熱以使其蒸發而生成氯化鎳氣體。然而，若考慮防止氯化鎳的氧化或吸濕、及能量效率，則下述方法是有利的：使金屬鎳與氯氣接觸而連續地產生氯化鎳氣體，將此氯化鎳氣體直接供給到還原步驟，接著與還原性氣體接觸而連續地還原氯化鎳氣體，以製造鎳微粉末。氣相還原法能夠以高產率得到個數平均粒徑D和結晶子徑d的比(d/D)為0.40以上的鎳粉末。 In the gas phase reduction method, the vaporized nickel chloride gas is reacted with a reducing gas such as hydrogen. In this case, the solid nickel chloride may be heated to evaporate to generate nickel chloride gas. However, in consideration of preventing the oxidation or moisture absorption of nickel chloride, and energy efficiency, the following method is advantageous: the nickel chloride gas is continuously generated by contacting metallic nickel with chlorine gas, and the nickel chloride gas is directly supplied to The reduction step is followed by contact with a reducing gas to continuously reduce the nickel chloride gas to produce nickel fine powder. The gas phase reduction method can obtain nickel powder having a ratio (d/D) of the number average particle diameter D to the crystallite diameter d of 0.40 or more with a high yield.

用於以鎳作為主要成分的合金粉末的製造方法時之氯化鎳氣體以外的金屬氯化物氣體，可舉出：三氯化矽(III)氣體、四氯化矽(IV)氣體、單矽烷氣體、氯化銅(I)氣體、氯化銅(II)氣體、氯化銀氣體、氯化鉬氣體(III)氣體、氯化鉬(V)氣體、氯化鐵(II)氣體、氯化鐵(III)氣體、氯化鉻(III)氣體、氯化鉻(VI)氣體、氯化鎢(II)氣體、氯化鎢(III)氣體、氯化鎢(IV)氣體、氯化鎢(V)氣體、氯化鎢(VI)氣體、氯化鉭(III)氣體、氯化鉭(V)氣體、氯化鈷氣體、氯化錸(III)氣體、氯化錸(IV)氣體、氯化錸(V)氣體、二硼烷(diborane)氣體、膦氣體等及它們的混合氣體。 Metal chloride gases other than nickel chloride gas used in the production method of alloy powders with nickel as the main component include: silicon trichloride (III) gas, silicon tetrachloride (IV) gas, and monosilane Gas, copper chloride (I) gas, copper chloride (II) gas, silver chloride gas, molybdenum chloride gas (III) gas, molybdenum chloride (V) gas, iron chloride (II) gas, chlorinated Iron (III) gas, chromium chloride (III) gas, chromium chloride (VI) gas, tungsten chloride (II) gas, tungsten chloride (III) gas, tungsten chloride (IV) gas, tungsten chloride ( V) gas, tungsten chloride (VI) gas, tantalum chloride (III) gas, tantalum chloride (V) gas, Cobalt chloride gas, rhenium chloride (III) gas, rhenium chloride (IV) gas, rhenium chloride (V) gas, diborane gas, phosphine gas, etc. and their mixed gas.

此外，就還原性氣體而言，可舉出：氫氣、硫化氫氣體、氨氣、一氧化碳氣體、甲烷氣體及它們的混合氣體。特佳為氫氣、硫化氫氣體、氨氣及它們的混合氣體。 In addition, the reducing gas includes hydrogen gas, hydrogen sulfide gas, ammonia gas, carbon monoxide gas, methane gas, and mixed gases thereof. Particularly preferred are hydrogen gas, hydrogen sulfide gas, ammonia gas and their mixed gas.

在利用氣相還原反應的鎳粉末的製造過程中，在氯化鎳氣體和還原性氣體接觸的瞬間生成鎳原子，鎳原子彼此碰撞、凝集，從而生成了鎳粒子並進行成長。然後，依照還原步驟中的氯化鎳氣體的分壓、溫度等的條件，決定生成的鎳粉末的粒徑。若利用如上述的鎳粉末的製造方法的話，則產生與氯氣的供給量相應的量的氯化鎳氣體，因此能藉由控制氯氣的供給量來調整供給至還原步驟的氯化鎳氣體的量，藉此，能控制生成的鎳粉末的粒徑。 In the manufacturing process of nickel powder using a gas-phase reduction reaction, nickel atoms are generated at the moment when the nickel chloride gas and the reducing gas come into contact, and the nickel atoms collide with each other and agglomerate, thereby generating nickel particles and growing. Then, the particle size of the nickel powder produced is determined in accordance with conditions such as the partial pressure and temperature of the nickel chloride gas in the reduction step. If the nickel powder manufacturing method as described above is used, the amount of nickel chloride gas corresponding to the supply amount of chlorine gas is generated. Therefore, the amount of nickel chloride gas supplied to the reduction step can be adjusted by controlling the supply amount of chlorine gas. By this, the particle size of the nickel powder produced can be controlled.

另外，氯化鎳氣體係在氯氣與金屬的反應中產生，因此與利用固體氯化鎳的加熱蒸發來使氯化鎳氣體產生的方法不同，不僅能減少載氣的使用，也可以依製造條件而不使用。由此，氣相還原反應，因載氣的使用量降低和與其相伴的加熱能量的降減而能夠謀求製造成本的削減。 In addition, the nickel chloride gas system is produced in the reaction of chlorine and metal. Therefore, it is different from the method of producing nickel chloride gas by heating and vaporizing solid nickel chloride. It can not only reduce the use of carrier gas, but also can depend on manufacturing conditions. Without using. Thus, the gas-phase reduction reaction can reduce the manufacturing cost due to the reduction in the amount of carrier gas used and the accompanying reduction in heating energy.

此外，藉由在氯化步驟中產生的氯化鎳氣體中混合惰性氣體，能夠控制還原步驟中的氯化鎳氣體的分壓。依此方式，藉由控制氯氣的供給量或供給至還原步驟中的氯化鎳氣體的分壓，能夠控制鎳粉末的粒徑，能夠抑制粒徑的偏差，同時能夠任意地設定粒徑。 In addition, by mixing an inert gas with the nickel chloride gas generated in the chlorination step, the partial pressure of the nickel chloride gas in the reduction step can be controlled. In this way, by controlling the supply of chlorine or supplying to the reduction The partial pressure of the nickel chloride gas in the step can control the particle size of the nickel powder, can suppress the variation of the particle size, and can set the particle size arbitrarily.

例如，起始原料的氯化鎳係先使純度為99.5%以上的粒狀、塊狀、板狀等的金屬鎳與氯氣反應以生成氯化鎳氣體。為了使反應充分進行，當時的溫度設為800℃以上，且設為鎳熔點的1453℃以下。若考慮反應速度和氯化爐的耐久性，則在實用上較佳為900℃~1100℃的範圍。 For example, the starting material of nickel chloride is made by first reacting metallic nickel with a purity of 99.5% or more in granular, massive, or plate-like shapes with chlorine gas to generate nickel chloride gas. In order to allow the reaction to proceed sufficiently, the temperature at that time is set to 800°C or higher, and set to 1453°C or lower of the melting point of nickel. Considering the reaction rate and the durability of the chlorination furnace, the range of 900°C to 1100°C is practically preferred.

接著，將此氯化鎳氣體直接供給至還原步驟，使其與氫氣等的還原性氣體接觸並反應。此時，能適當用氬、氮等的惰性氣體稀釋氯化鎳氣體以控制氯化鎳氣體的分壓。藉由控制氯化鎳氣體的分壓，能夠控制還原部中生成的金屬粉末的粒度分布等的品質。藉此，能任意地設定生成的金屬粉末的品質，同時能使品質穩定。還原反應的溫度只要在足以使反應完成的溫度以上即可，較佳為鎳的熔點以下，若考慮經濟性，則900℃~1100℃是實用的。 Next, this nickel chloride gas is directly supplied to the reduction step, and it is brought into contact with and reacted with a reducing gas such as hydrogen. At this time, the nickel chloride gas can be appropriately diluted with inert gas such as argon and nitrogen to control the partial pressure of the nickel chloride gas. By controlling the partial pressure of the nickel chloride gas, it is possible to control the quality of the particle size distribution and the like of the metal powder produced in the reduction section. Thereby, the quality of the produced metal powder can be arbitrarily set, and the quality can be stabilized. The temperature of the reduction reaction may be at least a temperature sufficient to complete the reaction, and is preferably lower than the melting point of nickel. In consideration of economy, 900°C to 1100°C is practical.

依此方式生成進行了還原反應的鎳粉末後，接著將生成的鎳粉末冷卻。冷卻時，為了防止由生成的鎳的一次粒子彼此凝集所造成的二次粒子的生成並得到所需粒徑的鎳粉末，理想的是藉由噴入氮氣等惰性氣體，使終止還原反應的1000℃附近的氣流急速冷卻至400~800℃左右。之後，利用例如袋式過濾器等來將生成的鎳粉末進行分離、回收。 After the reduction reaction of nickel powder is produced in this way, the produced nickel powder is then cooled. During cooling, in order to prevent the formation of secondary particles caused by the agglomeration of primary nickel particles and obtain nickel powder with the desired particle size, it is ideal to spray inert gas such as nitrogen to terminate the reduction reaction. The airflow around ℃ rapidly cools down to about 400~800℃. After that, the produced nickel powder is separated and recovered using, for example, a bag filter.

在利用噴霧熱分解法的鎳粉末的製造方法中，以熱分解性鎳化合物為原料，具體而言，包含硝酸鹽、硫酸鹽、羥基硝酸鹽、羥基硫酸鹽、氯化物、銨錯合物、磷酸鹽、羧酸鹽、烷氧基化合物等的1種或2種以上。將包含此鎳化合物的溶液噴霧，製作微細的液滴。作為此時的溶媒，可使用水、醇、丙酮、醚等。此外，噴霧的方法係利用超音波或雙重噴射噴嘴等的噴霧方法進行。依此方式操作以作成微細的液滴，在高溫下加熱以將金屬化合物進行熱分解，生成鎳粉末。此時的加熱溫度在所使用的特定的鎳化合物熱分解的溫度以上，較佳為金屬的熔點附近。 In the manufacturing method of nickel powder by spray thermal decomposition method , Using thermally decomposable nickel compounds as raw materials, specifically, containing nitrates, sulfates, hydroxynitrates, hydroxysulfates, chlorides, ammonium complexes, phosphates, carboxylates, alkoxy compounds, etc. One kind or two or more kinds. The solution containing this nickel compound is sprayed to produce fine droplets. As the solvent in this case, water, alcohol, acetone, ether, etc. can be used. In addition, the spraying method is performed by a spraying method such as ultrasonic wave or dual spray nozzle. Operate in this way to make fine droplets, which are heated at a high temperature to thermally decompose the metal compound to produce nickel powder. The heating temperature at this time is higher than the temperature at which the specific nickel compound used is thermally decomposed, and is preferably near the melting point of the metal.

在利用液相法的鎳粉末的製造方法中，將包含硫酸鎳、氯化鎳或鎳錯合物的鎳水溶液添加到氫氧化鈉等鹼金屬氫氧化物中等，使其接觸而生成鎳氫氧化物，接著用肼等還原劑將鎳氫氧化物還原，以得到金屬鎳粉末。依此方式而生成的金屬鎳粉末，為了得到均勻的粒子而根據需要進行粉碎處理。 In the method of producing nickel powder by the liquid phase method, a nickel aqueous solution containing nickel sulfate, nickel chloride, or nickel complex is added to alkali metal hydroxides such as sodium hydroxide, etc., and contacted to produce nickel hydroxide The nickel hydroxide is then reduced with a reducing agent such as hydrazine to obtain metallic nickel powder. The metallic nickel powder produced in this way is pulverized as necessary in order to obtain uniform particles.

用以上方法所得到的鎳粉末，為了除去殘留的原料，較佳為使其分散在液相中並進行洗滌。例如，在控制了pH、溫度的特定條件下，使用以上方法所得到的鎳粉末懸浮在碳酸水溶液中而進行處理。藉由用碳酸水溶液進行處理，能充分除去附著在鎳粉末的表面的氯等雜質，同時除去在鎳粉末的表面上存在的氧化鎳等的氧化物、氫氧化鎳等的氫氧化物、因粒子彼此的摩擦等而從表面離開所形成的微粒，能夠利用水中的溶存氧再形成包含氧化鎳和氫氧化鎳的薄且均勻的被膜。作為利用碳酸水溶液的處理方法，能夠是混合鎳粉末和碳酸水溶液的方法，或者是將二氧化碳氣體吹入暫時用純水洗滌鎳粉末後的水漿料中、或是將碳酸水溶液添加至暫時用純水洗滌鎳粉末後的水漿料中來進行處理。 In order to remove the remaining raw material, the nickel powder obtained by the above method is preferably dispersed in the liquid phase and washed. For example, under specific conditions with controlled pH and temperature, the nickel powder obtained by the above method is suspended in an aqueous carbonic acid solution and processed. By treating with a carbonic acid aqueous solution, impurities such as chlorine adhering to the surface of the nickel powder can be sufficiently removed, and at the same time, oxides such as nickel oxide, hydroxides such as nickel hydroxide, and particles present on the surface of the nickel powder can be removed. The particles formed when they are separated from the surface due to friction between each other can re-form a thin and uniform film containing nickel oxide and nickel hydroxide using the dissolved oxygen in the water. As profit The treatment method with carbonated aqueous solution can be a method of mixing nickel powder and carbonated aqueous solution, or blowing carbon dioxide gas into the water slurry after the nickel powder is temporarily washed with pure water, or adding carbonated aqueous solution to temporarily pure water The nickel powder is washed in the water slurry for treatment.

使本發明的鎳粉末含有硫的方法，沒有特別的限定，例如，能採用以下的方法。 The method for making the nickel powder of the present invention contain sulfur is not particularly limited. For example, the following methods can be adopted.

(1)在上述還原反應中添加含硫氣體的方法 (1) Method of adding sulfur-containing gas to the above reduction reaction

(2)將鎳粉末與含硫氣體接觸並進行處理的方法 (2) Method of contacting nickel powder with sulfur-containing gas and processing it

(3)將鎳粉末和固體的含硫化合物進行乾式混合的方法 (3) Method of dry mixing nickel powder and solid sulfur-containing compound

(4)將含硫化合物溶液添加至使鎳粉末分散在液相中的漿料中的方法 (4) Method of adding sulfur-containing compound solution to slurry in which nickel powder is dispersed in liquid phase

(5)使含硫氣體在使鎳粉末分散在液相中的漿料中起泡的方法 (5) Method of foaming sulfur-containing gas in a slurry in which nickel powder is dispersed in a liquid phase

特別是，從能精密地控制含硫量的方面、能均勻地添加硫的觀點出發，較佳為(1)及(4)的方法。在(1)、(2)、(5)的方法中所使用的含硫氣體沒有特別的限定，能將硫蒸氣、二氧化硫氣體、硫化氫氣體等的在還原步驟的溫度下為氣體的氣體直接或者稀釋後使用。其中，從常溫下為氣體且易於控制流量的方面、混入雜質的疑慮低的方面出發，二氧化硫氣體、及硫化氫氣體是有利的。 Particularly, the methods (1) and (4) are preferable from the viewpoint that the sulfur content can be precisely controlled and the sulfur can be added uniformly. The sulfur-containing gas used in the methods (1), (2), and (5) is not particularly limited. Gases such as sulfur vapor, sulfur dioxide gas, hydrogen sulfide gas, etc., which are gas at the temperature of the reduction step, can be directly Or use after dilution. Among them, sulfur dioxide gas and hydrogen sulfide gas are advantageous in terms of being a gas at room temperature and being easy to control the flow rate, and in terms of being less likely to be mixed with impurities.

前述的洗滌步驟及加硫步驟之後，將鎳粉末漿料進行乾燥。乾燥方法沒有特別的限定，能使用已知的方法。具體而言，可舉出：使其與高溫的氣體接觸以進行乾燥的氣流乾燥、加熱乾燥、真空乾燥等。其中，氣流乾燥係基於粒子彼此的碰撞而沒有含硫層的破壞，因而較佳。 After the aforementioned washing step and vulcanizing step, the nickel powder slurry is dried. The drying method is not particularly limited, and a known method can be used. Specifically, you can cite: contact with high temperature gas to Airflow drying, heat drying, vacuum drying, etc. are performed for drying. Among them, the airflow drying system is based on the collision of particles with each other without destroying the sulfur-containing layer, which is preferable.

對依上述方式所得到的鎳粉末，以特定的條件施加氧化處理。作為氧化處理的具體方法，可舉出：在包含氧化性氣體(例如，氧氣、臭氧氣體)的氣體環境下(例如，空氣中、氧氣的氣體環境中、包含氧氣的惰性氣體(氮、氬等)的氣體環境下等)，進行加熱處理的方法。此時的最適的加熱處理溫度係依粒徑而異，就積層陶瓷電容器的製造步驟中所使用的平均粒徑250nm以下而言，較佳為140~180℃，特別是，就平均粒徑140~250nm而言，較佳為在空氣中、在160~180℃下保持1分鐘~4小時。以在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比成為55.0~80.0%，金屬鎳的波峰對Ni2p_3/2整體光譜的面積比成為5.0~15.0%的方式，調整上述熱處理條件(溫度、時間)，適當地進行。依此方式，藉由將鎳粉末進行氧化處理，可形成更加牢固的氧化鎳的被膜。 The nickel powder obtained as described above is subjected to oxidation treatment under specific conditions. As a specific method of oxidation treatment, there can be mentioned: in a gas environment containing oxidizing gas (for example, oxygen, ozone gas) (for example, in air, in a gas environment of oxygen, inert gas containing oxygen (nitrogen, argon, etc.) ) In the gas environment, etc.), the method of heating treatment. The optimum heat treatment temperature at this time varies depending on the particle size. The average particle size used in the manufacturing step of the multilayer ceramic capacitor is 250 nm or less, preferably 140 to 180°C, and in particular, the average particle size is 140 For ~250nm, it is preferable to keep it in the air at 160-180°C for 1 minute to 4 hours. In the analysis of the chemical bonding state of nickel in the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS), the area ratio of the peak attributable to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 becomes 55.0~ 80.0%, so that the area ratio of the peak of metallic nickel to the entire spectrum of Ni2p _3/2 becomes 5.0 to 15.0%, and the heat treatment conditions (temperature, time) described above are adjusted and performed appropriately. In this way, by oxidizing the nickel powder, a stronger nickel oxide film can be formed.

本發明的鎳粉末能用作膏原料。更佳為包含上述鎳粉末、和有機溶媒的鎳膏。此外，可以根據需要，包含乙基纖維素等的有機黏結劑、分散劑、及要塗布的陶瓷的未燒成粉。 The nickel powder of the present invention can be used as a paste raw material. More preferably, it is a nickel paste containing the above-mentioned nickel powder and an organic solvent. In addition, if necessary, an organic binder such as ethyl cellulose, a dispersant, and unfired powder of ceramics to be coated may be contained.

此鎳膏，能夠添加上述鎳粉末、和例如萜品醇等的有機溶媒、根據需要的乙基纖維素等的有機黏結劑、分散劑、及要塗布的陶瓷的未燒成粉，用以3根輥混練的這樣的公知方法來容易地製造特性較佳的鎳膏。作為有機溶媒，可舉出：醇、丙酮、丙醇、乙酸乙酯、乙酸丁酯、醚、石油醚、礦油精、其他的烷烴系烴溶劑，或者是丁基卡必醇、萜品醇、二氫萜品醇、丁基卡必醇乙酸酯、二氫萜品醇乙酸酯、乙酸二氫香芹酯(dihydrocarvyl acetate)、乙酸香芹酯(carvyl acetate)、乙酸萜品酯、乙酸芳樟酯等的乙酸酯系，丙酸二氫萜品酯、丙酸二氫香芹酯、丙酸異莰酯等的丙酸酯系溶劑，乙基賽路蘇、丁基賽路蘇等的賽路蘇類、芳香族類、鄰苯二甲酸二乙酯等。 This nickel paste can be added with the above-mentioned nickel powder, organic solvents such as terpineol, and organic binders such as ethyl cellulose as needed. The powder, the dispersant, and the unfired powder of the ceramic to be applied can be easily produced by the known method of kneading with three rolls to produce nickel paste with better properties. Examples of organic solvents include: alcohol, acetone, propanol, ethyl acetate, butyl acetate, ether, petroleum ether, mineral spirits, other alkane-based hydrocarbon solvents, or butyl carbitol, terpineol , Dihydroterpineol, butyl carbitol acetate, dihydroterpineol acetate, dihydrocarvyl acetate (dihydrocarvyl acetate), carvyl acetate (carvyl acetate), terpineyl acetate, Acetate-based solvents such as linalyl acetate, propionate-based solvents such as dihydroterpinyl propionate, dihydrocarvyl propionate, isobornyl propionate, ethyl siloxol, butyl silyl Cyrus, aromatic, diethyl phthalate, etc.

此外，作為有機黏結劑，較佳為樹脂結合劑，例如，可舉出：乙基纖維素、聚乙酸乙烯酯、丙烯酸樹脂、醇酸樹脂等。 Moreover, as an organic binder, a resin binder is preferable, for example, ethyl cellulose, polyvinyl acetate, acrylic resin, alkyd resin, etc. are mentioned.

作為分散劑，可使用周知的適當分散劑，能使用例如乙烯基系聚合物、聚羧酸胺鹽、聚羧酸系等。 As a dispersing agent, a well-known appropriate dispersing agent can be used, for example, a vinyl polymer, a polycarboxylic acid amine salt, a polycarboxylic acid type etc. can be used.

依上述方式所得到的本發明的鎳粉末，係其表面具有具有某種程度的厚度和緻密度的包含氧化鎳及氫氧化鎳的被膜，因此在積層陶瓷電容器的製造步驟中顯示優異的燒結行為，能防止脫層的產生。更具體而言，在進行加熱處理之際，氧化還原反應所造成的體積變化或重量變化少是當然的，燒結開始溫度比習知鎳粉末還高，因此變得更接近在製造積層陶瓷電容器之際使用的介電體的燒結開始溫度，其結果，能有效地防止脫層的發生。 The nickel powder of the present invention obtained in the above-mentioned manner has a coating film containing nickel oxide and nickel hydroxide with a certain degree of thickness and density on the surface, and therefore exhibits excellent sintering behavior in the manufacturing process of multilayer ceramic capacitors , Can prevent delamination. More specifically, when the heat treatment is performed, the volume change or the weight change caused by the oxidation-reduction reaction is of course less, and the sintering start temperature is higher than that of conventional nickel powder, so it becomes closer to the manufacturing of multilayer ceramic capacitors. As a result, the sintering start temperature of the dielectric body used in the world can effectively prevent the occurrence of delamination.

[實施例] [Example]

接著，舉出實施例及比較例以進一步地具體說明本發明，但這只是例示，並非限制本發明。 Next, examples and comparative examples are given to further specifically explain the present invention, but these are only examples and do not limit the present invention.

[實施例1] [Example 1]

使氯化鎳和氫反應的氣相反應法之後，在純水中及碳酸水溶液中進行洗滌，在使鎳粉末分散在液相中的漿料中添加含硫化合物，使其進行乾燥，製備鎳粉末。確認所得到的鎳粉末的個數平均粒徑為191nm、平均高寬比為1.2、平均圓形度係數為0.68的球狀鎳粉。此外，比表面積為4.0m²/g，比表面積徑為168nm。另外，個數平均粒徑d和比表面積徑的比d/D為0.88。 After the gas phase reaction method of reacting nickel chloride and hydrogen, washing is performed in pure water and an aqueous carbonic acid solution, a sulfur-containing compound is added to the slurry in which the nickel powder is dispersed in the liquid phase, and it is dried to prepare nickel powder. It was confirmed that the obtained nickel powder had a spherical nickel powder with a number average particle size of 191 nm, an average aspect ratio of 1.2, and an average circularity coefficient of 0.68. In addition, the specific surface area was 4.0 m ² /g, and the specific surface area diameter was 168 nm. In addition, the ratio d/D of the number average particle diameter d to the specific surface area diameter was 0.88.

將上述鎳粉末在氧化性氣體環境下、在175℃下進行4小時的氧化處理，得到鎳粉末。將含氧率、平均粒徑、X射線光電子分光分析(XPS)測定、分散性評價、氧化鎳及氫氧化鎳的被膜的厚度、2%熱收縮溫度、比表面積徑、個數平均粒徑和比表面積徑的比的測定結果顯示在表1，將燒結行為的結果顯示在圖1。 The nickel powder was subjected to oxidation treatment at 175°C for 4 hours in an oxidizing gas environment to obtain nickel powder. The oxygen content, average particle size, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of nickel oxide and nickel hydroxide film, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter and The measurement results of the ratio of specific surface area to diameter are shown in Table 1, and the results of the sintering behavior are shown in FIG. 1.

此外，實施例1的鎳粉末，若進行紅外線吸收光譜分析，則觀察到肇因於與金屬鎳化學鍵結的OH基的波數為3600~3700cm^-1的吸收波峰。 In addition, when the nickel powder of Example 1 was analyzed by infrared absorption spectroscopy, an absorption peak of 3600 to 3700 cm ⁻¹ was observed due to the OH group chemically bonded to metallic nickel.

[比較例1] [Comparative Example 1]

除了在氧化性氣體環境下、在155℃下進行2小時的氧化處理外，與實施例1同樣地製作試料，得到鎳粉末。將含氧率、平均粒徑、X射線光電子分光分析(XPS)測定、分散性評價、氧化鎳及氫氧化鎳的被膜的厚度、2%熱收縮溫度、比表面積徑、個數平均粒徑和比表面積徑的比的測定結果顯示在表1，將燒結行為的結果顯示在圖1。 Except that the oxidation treatment was performed at 155°C for 2 hours in an oxidizing gas environment, a sample was produced in the same manner as in Example 1 to obtain nickel powder. The oxygen content, average particle size, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of nickel oxide and nickel hydroxide film, 2% heat The measurement results of the shrinkage temperature, the specific surface area diameter, the number average particle diameter, and the ratio of the specific surface area diameter are shown in Table 1, and the results of the sintering behavior are shown in FIG. 1.

[比較例2] [Comparative Example 2]

除了不進行氧化處理外，與實施例1同樣地製作試料，得到鎳粉末。將含氧率、平均粒徑、X射線光電子分光分析(XPS)測定、分散性評價、氧化鎳及氫氧化鎳的被膜的厚度、2%熱收縮溫度、比表面積徑、個數平均粒徑和比表面積徑的比的測定結果顯示在表1，將燒結行為的結果顯示在圖1。 Except for not performing the oxidation treatment, a sample was prepared in the same manner as in Example 1 to obtain nickel powder. The oxygen content, average particle size, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of nickel oxide and nickel hydroxide film, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter and The measurement results of the ratio of specific surface area to diameter are shown in Table 1, and the results of the sintering behavior are shown in FIG. 1.

[比較例3] [Comparative Example 3]

除了在氧化性氣體環境下、在230℃下進行2小時的氧化處理外，與實施例1同樣地製作試料，得到鎳粉末。將含氧率、平均粒徑、X射線光電子分光分析(XPS)測定、分散性評價、氧化鎳及氫氧化鎳的被膜的厚度、2%熱收縮溫度、比表面積徑、個數平均粒徑和比表面積徑的比的測定結果顯示在表1，將燒結行為的結果顯示在圖1。 Except for performing the oxidation treatment at 230°C for 2 hours in an oxidizing gas environment, a sample was prepared in the same manner as in Example 1 to obtain nickel powder. The oxygen content, average particle size, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of nickel oxide and nickel hydroxide film, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter and The measurement results of the ratio of specific surface area to diameter are shown in Table 1, and the results of the sintering behavior are shown in FIG. 1.

測定 Determination

以下，顯示上述各實施例及比較例的鎳粉末的含氧率、平均粒徑、基於X射線光電子分光分析(XPS)的金屬鎳和表面氧化物、表面氫氧化物的面積的比例、分散性評價、氧化鎳及氫氧化鎳的被膜的厚度、2%熱收縮溫度的測定方法。 The following shows the oxygen content, average particle size, the area ratio of metal nickel to surface oxides and surface hydroxides, and dispersibility of the nickel powders of the foregoing Examples and Comparative Examples based on X-ray Photoelectron Spectroscopy (XPS) Evaluation, method for measuring the thickness of the coating film of nickel oxide and nickel hydroxide, and the 2% heat shrinkage temperature.

1)含氧率 1) Oxygen content

將試料的鎳粉末填充於鎳製的膠囊，將其放入石墨坩堝，在氬氣環境中加熱至500℃，利用傅立葉轉換型紅外分光光度計將此時產生的一氧化碳進行定量，求出鎳粉末中的含氧率。 The nickel powder of the sample was filled in a nickel capsule, placed in a graphite crucible, heated to 500°C in an argon atmosphere, and Fourier transform red The external spectrophotometer quantified the carbon monoxide generated at this time to obtain the oxygen content in the nickel powder.

2)平均粒徑 2) Average particle size

利用電子顯微鏡拍攝試料的照片，由該照片使用影像解析軟體，測定900個粉末的粒徑，算出其個數平均粒徑。此時，粒徑係包入粒子的最小圓的直徑。 A photograph of the sample was taken with an electron microscope, and the particle size of 900 powders was measured using image analysis software from the photograph, and the number average particle size was calculated. At this time, the particle size is the diameter of the smallest circle that encloses the particles.

3)X射線光電子分光分析(XPS)測定 3) X-ray photoelectron spectroscopy (XPS) measurement

使用X射線光電子分光分析裝置(Thermo Fisher Scientific股份公司製，K-ALPHA⁺)，測定粉末表面的Ni2p_3/2光譜，使用分析裝置附屬的解析軟體「Avantage Ver.5.951」，將該光譜進行波峰分離，算出金屬鎳的波峰對Ni2p_3/2整體光譜的面積比、歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比、歸屬於鎳和氫氧化物的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比。 Measure the Ni2p _3/2 spectrum on the powder surface using an X-ray photoelectron spectroscopic analyzer (manufactured by Thermo Fisher Scientific Co., Ltd., K-ALPHA ⁺ ), and use the analysis software "Avantage Ver.5.951" attached to the analyzer to peak the spectrum Separate and calculate the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 , the area ratio of the peak attributable to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 , and the bond between nickel and hydroxide The area ratio of the peak of the state to the overall spectrum of Ni2p _3/2 .

4)分散性評價 4) Evaluation of dispersion

將鎳粉末0.05g放入純水100g，以超音波分散機(Sonic Technology股份公司，GSD600AT)進行分散1分鐘。試料的分散處理後，使用3μm的薄膜過濾器(membrane filter)進行減壓過濾，若全部量漿料通過薄膜過濾器擁有的時間為30秒鐘以內的話，則設為良好(○)，在花費比30秒鐘多的時間的情況下，設為不良(×)。 0.05 g of nickel powder was put into 100 g of pure water, and dispersed with an ultrasonic disperser (Sonic Technology Co., Ltd., GSD600AT) for 1 minute. After the sample is dispersed, it is filtered under reduced pressure using a 3μm membrane filter. If the time for the entire amount of slurry to pass through the membrane filter is within 30 seconds, it is set as good (○). When the time is longer than 30 seconds, it is set as bad (×).

5)氧化鎳及氫氧化鎳的被膜的厚度 5) The thickness of the coating film of nickel oxide and nickel hydroxide

將鎳粉末直接撒在貼有火棉膠膜的銅製薄片網篩上，之後使其蒸鍍碳而作成測定試料。接著，使用穿透型電子顯微鏡(日本電子股份公司製，JEM-2100F)，在加速電壓200kV的條件下觀察測定試料的晶格影像，對鎳粉末表面的氧化鎳及氫氧化鎳的被膜厚度進行6點測定，算出其平均。 The nickel powder was sprinkled directly on a copper sheet mesh sieve pasted with a collodion film, and then carbon was vapor-deposited to prepare a measurement sample. Next, using a transmission electron microscope (made by JEOL Ltd., JEM-2100F), Under the condition of a voltage of 200 kV, the lattice image of the measurement sample was observed, and the film thickness of nickel oxide and nickel hydroxide on the surface of the nickel powder was measured at 6 points, and the average was calculated.

6)2%熱收縮溫度及燒結行為 6) 2% heat shrinkage temperature and sintering behavior

混合鎳粉末1g、樟腦3重量%及丙酮3重量%，填充於內徑5mm、長度10mm的圓柱狀模具，之後施加面壓1噸的荷重作成試驗片。將此試驗片，使用熱膨脹收縮行為(diratometry)測定裝置(TMA，8310，Rigaku股份公司製)，在氮氣(含有氫氣2%)的氣體環境下、在升溫速度10℃/分鐘的條件下進行測定。此外，將利用熱膨脹收縮行為測定裝置(TMA)所測定的2%熱收縮的溫度作為2%熱收縮溫度。 1 g of nickel powder, 3% by weight of camphor, and 3% by weight of acetone were mixed, filled in a cylindrical mold with an inner diameter of 5 mm and a length of 10 mm, and then a load of 1 ton of surface pressure was applied to prepare a test piece. This test piece was measured using a thermal expansion and contraction behavior (diratometry) measuring device (TMA, 8310, manufactured by Rigaku Co., Ltd.) in a nitrogen gas (containing 2% hydrogen) gas environment at a temperature increase rate of 10°C/min. . In addition, the 2% heat shrinkage temperature measured by the thermal expansion and contraction behavior measuring device (TMA) is defined as the 2% heat shrinkage temperature.

7)比表面積 7) Specific surface area

使用BET比表面積測定裝置(Mountech股份公司製)，在氮氣流下160℃、1小時的前處理後，進行比表面積測定，由該比表面積S，使用下述式(式1)算出比表面積徑d。此處，ρ為鎳的真密度。另外，算出個數平均粒徑D和比表面積徑d的比。 Using a BET specific surface area measuring device (manufactured by Mountech Co., Ltd.), the specific surface area was measured after a pretreatment at 160°C for 1 hour under a nitrogen stream. From the specific surface area S, the specific surface area diameter d was calculated using the following formula (Equation 1) . Here, ρ is the true density of nickel. In addition, the ratio of the number average particle diameter D to the specific surface area diameter d was calculated.

由表1可知，表面氧化物的比例較比較例1、2的鎳粉末高的實施例1的鎳粉末，同樣地其分散性評價較表面氧化物的比例高的比較例3的鎳粉末優異。由此可推定，實施例1的鎳粉末係分散性優異，因此在製造積層陶瓷電容器之際鎳粉和共同材料的混合變得充分，可謀求防止脫層。 It can be seen from Table 1 that the nickel powder of Example 1, which has a higher ratio of surface oxides than the nickel powders of Comparative Examples 1 and 2, also has better dispersibility evaluation than the nickel powder of Comparative Example 3, which has a higher ratio of surface oxides. From this, it can be presumed that the nickel powder system of Example 1 is excellent in dispersibility, and therefore the mixing of nickel powder and common materials becomes sufficient when the multilayer ceramic capacitor is manufactured, and delamination can be prevented.

此外，知道了實施例1的鎳粉末的被膜厚度較比較例1、2的鎳粉末大。 In addition, it was found that the thickness of the coating film of the nickel powder of Example 1 was larger than that of the nickel powders of Comparative Examples 1 and 2.

另外，在2%熱收縮溫度方面，實施例1的鎳粉末較比較例1、2的鎳粉末高，此外，在圖1的燒結行為中，完全沒有在300~400℃的低溫區域的體積變化而燒結行為穩定。 In addition, in terms of the 2% heat shrinkage temperature, the nickel powder of Example 1 is higher than the nickel powders of Comparative Examples 1 and 2. In addition, in the sintering behavior of Fig. 1, there is no volume change in the low temperature region of 300 to 400°C. The sintering behavior is stable.

由以上的結果，可推定：本發明的鎳粉末係在積層陶瓷電容器的製造步驟中顯示優異的燒結行為，而且分散性優異，因此其結果，可謀求防止脫層。 From the above results, it can be inferred that the nickel powder of the present invention exhibits excellent sintering behavior in the manufacturing process of a multilayer ceramic capacitor and is excellent in dispersibility. As a result, delamination can be prevented.

如同以上說明，根據本發明的鎳粉末，在平均粒徑250nm以下中，與習知鎳粉末相比，燒結行為非常穩定，沒有在低溫區域的鎳粉末的收縮及膨脹，而且分散性優異，由此，使用了本發明的鎳粉末的膏，發揮了在積層陶瓷電容器的製造過程中能夠防止脫層的發生這樣的效果。 As explained above, the nickel powder according to the present invention has an average particle diameter of 250 nm or less, compared with the conventional nickel powder, the sintering behavior is different. Normally stable, there is no shrinkage and expansion of nickel powder in the low temperature region, and excellent dispersibility. Therefore, the paste using the nickel powder of the present invention can prevent delamination during the manufacturing process of multilayer ceramic capacitors. Effect.

根據本發明，能提供與習知鎳粉末相比，燒結行為非常穩定，沒有在低溫區域的鎳粉末的收縮及膨脹，而且分散性優異，適合MLCC的製造的鎳粉末。 According to the present invention, compared with conventional nickel powders, it is possible to provide nickel powders that are very stable in sintering behavior, have no shrinkage and expansion of nickel powders in low temperature regions, and are excellent in dispersibility, and are suitable for the production of MLCC.

Claims

一種鎳粉末，其特徵為：具有包含氧化鎳及氫氧化鎳的被膜，平均粒徑為250nm以下，在基於X射線光電子分光法(XPS)的鎳粉末表面層的鎳的化學鍵結狀態的解析中，歸屬於鎳和氧的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為55.0~80.0%，金屬鎳的波峰對Ni2p_3/2整體光譜的面積比為5.0~15.0%，歸屬於鎳和氫氧基的鍵結狀態的波峰對Ni2p_3/2整體光譜的面積比為5.0~40.0%，該被膜的厚度平均為3.0~5.0nm。 A nickel powder characterized by having a coating film containing nickel oxide and nickel hydroxide, with an average particle size of 250 nm or less, in the analysis of the chemical bonding state of nickel on the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS) , The area ratio of the peak attributable to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 is 55.0~80.0%, and the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 is 5.0~15.0%. The area ratio of the peaks of the bonding state of nickel and hydroxyl groups to the overall spectrum of Ni2p _3/2 is 5.0 to 40.0%, and the thickness of the film is 3.0 to 5.0 nm on average.