TW201736617A

TW201736617A - Nickel powder

Info

Publication number: TW201736617A
Application number: TW106100782A
Authority: TW
Inventors: 大栗雅人; 淺井剛; 吉田貢
Original assignee: 東邦鈦股份有限公司
Priority date: 2016-01-12
Filing date: 2017-01-11
Publication date: 2017-10-16
Also published as: JP6876001B2; WO2017122689A1; JPWO2017122689A1; CN108430673A; TWI716526B; CN108430673B; KR102589697B1; KR20180101504A

Abstract

To provide a nickel powder suitable for use in electroconductive pastes which exhibits excellent sintering behavior and dispersibility and, as a result, can prevent delamination. The nickel powder has a coating film comprising nickel oxide and nickel hydroxide and has an average particle diameter of 250 nm or smaller. In analysis by X-ray photoelectron spectroscopy (XPS) for the chemically bonded states of the nickel contained in the surface layer of the nickel powder, the areal proportion of the peak assigned to nickel/oxygen bonding to the whole Ni2p3/2 spectrum is 55.0-80.0%, the areal proportion of the peak assigned to nickel metal to the whole Ni2p3/2 spectrum is 5.0-15.0%, and the areal proportion of the peak assigned to nickel/hydroxy group bonding to the whole Ni2p3/2 spectrum is 5.0-40.0%. The coating film has an average thickness of 3.0-5.0 nm.

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 a nickel powder suitable for use in a conductive paste, and more particularly to a nickel powder excellent in sintering characteristics and dispersibility used in an internal electrode of a multilayer ceramic capacitor.

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 the like are used as a conductive paste for electronic materials, particularly for internal electrodes of laminated ceramic capacitors. . In general, a multilayer ceramic capacitor has a structure in which a dielectric ceramic layer is alternately overlapped and a metal layer serving as an internal electrode, and an external portion connected to a metal layer of the internal electrode is connected to both ends of the dielectric ceramic layer. electrode. Here, as a material constituting the dielectric body, a material having a high dielectric constant such as barium titanate, barium titanate or cerium oxide can be used as a main component. On the other hand, as the metal constituting the internal electrode, the above-mentioned noble metal powder or base metal powder can be used, but recently, a cheaper electronic material is required. Therefore, development of a laminated ceramic capacitor using the latter-grade metal powder is actively carried out, in particular, It is represented by metal 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, a laminated ceramic capacitor using metal nickel powder as an internal electrode is generally produced by the following method. That is, barium titanate, etc. The dielectric powder is mixed with an organic binder and suspended, and formed into a sheet shape by a doctor blade method to form a dielectric green sheet. On the other hand, the metallic nickel powder for the internal electrode is mixed with an organic compound such as an organic solvent, a plasticizer or an organic binder to form a metallic nickel powder paste, which is printed on the green sheet by a screen printing method. Then, drying, laminating, and pressure bonding are performed, and the organic component is removed by heat treatment, and then further heated in a reducing gas atmosphere of hydrogen gas, and calcined at a temperature of 1000 to 1300 ° C or higher, and then, in a dielectric body. The external electrodes are baked at both ends of the ceramic layer to obtain a laminated 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 method for producing a multilayer ceramic capacitor as described above, the metal paste is printed on the dielectric green sheet, and after laminating and pressure-bonding, the heat treatment system for evaporating and removing the organic component by heat treatment is usually in the atmosphere at 250 to 400. Perform at °C. In this way, heat treatment is performed in an oxidizing gas atmosphere, and thus the metallic nickel powder is oxidized, thus causing volume expansion. At the same time, the metallic nickel powder begins to sinter and begins to cause shrinkage of the volume.

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 manner, in the step of manufacturing the laminated ceramic capacitor, the volume change caused by the expansion-contraction occurs in the metallic nickel powder due to the redox-sintering reaction from the low temperature region near 300 °C. At this time, if the oxidation behavior or the sintering behavior of the metallic nickel powder is unstable at a low temperature stage, strain is likely to occur in the dielectric layer and the electrode layer, and as a result, cracking, peeling, or the like is caused, which is called delamination. The problem of the destruction of the layered structure.

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 means for solving the delamination problem as described above. For example, in Japanese Patent Laid-Open No. Hei 8-246001, A metal nickel powder having a certain taper density with respect to a specific particle diameter and having a certain limit or more is described, and it is described that the nickel powder and the dielectric body dispersed in the paste are fired by using such a metal nickel powder. When a capacitor is fabricated, 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 publication, the corresponding effect is improved in the purpose of improving the sintering behavior, but it is not necessarily sufficient in the method of preventing delamination, 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, a nickel powder capable of preventing delamination is disclosed in Japanese Laid-Open Patent Publication No. 2000-045001, Japanese Patent Publication No. 2000-045002, and International Publication No. WO2004/020128. Specifically, the nickel powder obtained by heat treatment in an oxidizing gas atmosphere 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 diameter smaller than 250 nm, the oxygen content is increased, and the aggregation of the nickel powder is increased. Therefore, when firing is performed in a reducing gas atmosphere, gas generation and volume change due to reduction of nickel powder oxide become large, and thus there arises a problem that a dense electrode film cannot be obtained and a laminated electron is caused. The cracking of the part, the problem of delamination, and the mixing with the co-material are insufficient due to the agglomerated nickel powder, causing a problem of delamination.

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。 Thus, the present invention has been made in view of the above problems of the prior art, and an object is to provide a nickel powder which exhibits excellent sintering behavior and a nickel powder having an average particle diameter of 250 nm or less used in a manufacturing step of a laminated ceramic capacitor. Dispersibility, as a result, can prevent delamination and is suitable for a conductive paste. More specifically, it is an object to provide a volume change or weight caused by a redox reaction at the time of heat treatment. Further, the sintering start temperature is higher than that of the conventional nickel powder, and is closer to the sintering start temperature of the dielectric used in the production of the laminated ceramic capacitor, and as a result, the delaminated conductive paste nickel powder can be prevented.

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 the laminated ceramic capacitor, a volume change caused by expansion-contraction occurs in the nickel powder due to the redox reaction, thereby causing delamination. Thereby, when a thick oxide film is densely formed on the surface of the nickel powder, oxidation can be suppressed 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 the metal nickel powder, and found that in the analysis of the chemical bonding state of nickel in the surface layer of the nickel powder by X-ray photoelectron spectroscopy (XPS), the sintering behavior is attributed to nickel and The peak of the oxygen bonding state changes to the area ratio of the Ni2p _3/2 overall spectral peak, and the metal nickel powder having a specific oxide film produced by a specific method is excellent in sintering characteristics, and thus the present invention has been completed.

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 in that it has a film containing nickel oxide and nickel hydroxide, and has an average particle diameter of 250 nm or less, and is chemically bonded to nickel in the surface layer of the nickel powder by X-ray photoelectron spectroscopy (XPS). In the analysis, the area ratio of the peak attributed to the bonding state of nickel to oxygen to the overall spectrum of Ni2p _3/2 is 55.0 to 80.0%, and the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 is 5.0 to 15.0%. The area ratio of the peak attributed to the bonding state of nickel and hydroxyl group 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.

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 exhibit excellent sintering behavior and dispersibility, and as a result, can prevent delamination and is suitable for a 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] [Formation of 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 nickel powder of the present invention has a number average particle diameter of 250 nm or less. More preferably, it is 30 to 250 nm, and it is more preferably in the range of 50 to 250 nm, and more preferably in the range of 140 to 250 nm. Further, the average particle diameter of the nickel powder of the present invention is a photograph of primary particles of nickel powder taken by a scanning electron microscope, and the image analysis software is used for the photograph, and the particle diameter of 500 or more particles is measured, and the particle size of the obtained nickel powder is determined. The distribution calculates the average number of particles. At this time, the particle diameter is the diameter of the smallest circle of 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。 Further, the ratio (d/D) of the number average particle diameter D to the specific surface diameter d of the nickel powder of the present invention is preferably 0.7 or more. The specific surface area diameter of the present invention means that the particles are assumed to be a true sphere and are calculated from the specific surface area of the nickel fine powder. When d/D is 0.7 or more, a good paste is easily obtained, and the film density of the film obtained by applying a paste is improved, and good sinterability is achieved in the manufacturing process of MLCC.

此外，鎳粉末的基於BET的比表面積較佳為2~30m²/g。 Further, the BET-based specific surface area of the nickel powder is preferably from 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。 Further, the particle shape of the nickel powder of the present invention is spherical. It is desirable to improve the 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 and minor diameters of the smallest ellipse encased in the particle. Further, 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, when the shape of the nickel powder is spherical, when the internal electrode of the MLCC is processed, the filling ratio is increased, 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 analysis of the chemical bonding state of nickel in the surface layer of nickel powder by X-ray photoelectron spectroscopy (XPS), and the peak of Ni2p _3/2 which is attributed to the bonding state of nickel and oxygen. The area ratio 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%, and the peak of the bonding state attributed to nickel and hydroxyl to 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 film has an average thickness of 3.0 to 5.0 nm.

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。 Further, when the nickel powder of the present invention is subjected to infrared absorption spectrum analysis, it has an absorption peak due to the wave number of the OH group chemically bonded to the metallic nickel of 3600 to 3700 cm ^-1 .

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 manner, a dense nickel oxide and nickel hydroxide film having a specific thickness is formed, and when heat treatment is performed, in particular, in the manufacturing step of the multilayer ceramic capacitor, 300 to 400 ° C for removing organic components can be used. The temperature and temperature are reduced, and the volume and weight changes caused by redox redox are reduced.

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 nickel powder of the present invention has a strong nickel oxide surface and Since the nickel hydroxide film is formed, the sintering start temperature is higher than that of the conventional nickel powder, and is closer to the sintering start temperature of the dielectric used in the production of the laminated ceramic capacitor. Thus, the nickel powder of the present invention is excellent in oxidation behavior or sintering behavior upon 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。 Further, the nickel powder of the present invention is excellent in 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 in the surface layer of nickel powder based on X-ray photoelectron spectroscopy (XPS), which is attributed to the peak attributed to metallic nickel, to nickel and The peak of the oxygen bonding state and the spectrum of the peak attributed to the bonding state of nickel and hydroxyl groups. The area ratio of each spectrum was subjected to peak separation of the obtained Ni ₂ p _3/2 spectrum, and the area of each spectrum was calculated, and the area ratio of each spectrum to the total of the spectra was obtained.

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。 In the film thickness of the present invention, a lattice image of a nickel powder sample was observed by a transmission electron microscope, and the film thickness on the surface of the nickel powder was measured at six points to obtain an average value.

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 the nickel powder by X-ray photoelectron spectroscopy (XPS), the area ratio of the peak attributed to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 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 attributed to the bonding state of nickel and hydroxyl to the overall spectrum of Ni2p _3/2 is 12.0~33.0%, the thickness of the nickel oxide and nickel hydroxide coatings is 3.5~4.5nm on average.

[鎳粉末的製造方法] [Method for Producing 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, for example, by a vapor phase method, a liquid phase method, or the like. Method of manufacturing. In particular, in order to easily control the particle diameter of the produced fine metal powder and to efficiently produce spherical particles, it is preferred to form nickel powder by bringing nickel chloride gas into contact with a reducing gas. A gas phase reduction method or a spray pyrolysis method in which a pyrolytic nickel compound is sprayed for thermal decomposition. In particular, from the viewpoint of precisely controlling the particle diameter of the produced nickel powder and preventing the generation of coarse particles, a gas phase reduction method in which a nickel chloride gas is brought into contact with a reducing gas is preferred.

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 vapor phase reduction method, a gas of vaporized nickel chloride is reacted with a reducing gas such as hydrogen. In this case, solid nickel chloride may also be heated to evaporate to form nickel chloride gas. However, if it is considered to prevent oxidation or moisture absorption of nickel chloride and energy efficiency, the following method is advantageous in that metal nickel is continuously contacted with chlorine gas to generate nickel chloride gas, and the nickel chloride gas is directly supplied thereto. The reduction step, followed by contact with a reducing gas, continuously reduces nickel chloride gas to produce a nickel fine powder. The vapor phase reduction method can obtain a nickel powder having a ratio (d/D) of the number average particle diameter D to the crystallite diameter d of 0.40 or more in 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。 Examples of the metal chloride gas other than the nickel chloride gas used in the method for producing an alloy powder containing nickel as a main component include ruthenium (III) chloride gas, ruthenium ( IV) tetrachloride gas, and monodecane. Gas, copper (I) gas, copper (II) chloride gas, silver chloride gas, molybdenum chloride gas (III) gas, molybdenum chloride (V) gas, iron (II) chloride gas, chlorination Iron (III) gas, chromium (III) chloride gas, chromium (VI) chloride gas, tungsten (II) chloride gas, tungsten (III) chloride gas, tungsten (IV) chloride gas, tungsten chloride ( V) gas, tungsten (VI) chloride gas, cerium (III) chloride gas, cerium (V) chloride gas, Cobalt chloride gas, ruthenium (III) chloride gas, ruthenium (IV) chloride gas, ruthenium (V) chloride gas, diborane gas, phosphine gas, and the like, and a mixed gas thereof.

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。 Further, examples of the reducing gas include hydrogen gas, hydrogen sulfide gas, ammonia gas, carbon monoxide gas, methane gas, and a mixed gas thereof. Particularly preferred are hydrogen, hydrogen sulfide gas, ammonia, and a mixture thereof.

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 production process of the nickel powder by the vapor phase reduction reaction, nickel atoms are generated at the moment of contact between the nickel chloride gas and the reducing gas, and the nickel atoms collide with each other and aggregate, thereby generating and growing nickel particles. Then, the particle size of the produced nickel powder is determined in accordance with conditions such as the partial pressure of the nickel chloride gas in the reduction step, temperature, and the like. When the method for producing nickel powder as described above is used, since the amount of nickel chloride gas corresponding to the supply amount of chlorine gas is generated, the amount of nickel chloride gas supplied to the reduction step can be adjusted by controlling the supply amount of chlorine gas. Thereby, the particle diameter of the produced nickel powder 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 generated in the reaction between chlorine gas and metal. Therefore, unlike the method of generating nickel chloride gas by heating and evaporation of solid nickel chloride, not only the use of the carrier gas but also the manufacturing conditions can be reduced. Not used. Thereby, the gas phase reduction reaction can reduce the manufacturing cost by reducing the amount of use of the carrier gas and reducing the heating energy associated therewith.

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。 Further, by mixing the inert gas in 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 it to reduction The partial pressure of the nickel chloride gas in the step can control the particle diameter of the nickel powder, and can suppress the variation in the particle diameter, and can set the particle diameter 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 nickel chloride of the starting material is first reacted with a metal such as a granular, massive or plate-like material having a purity of 99.5% or more and chlorine gas to form a nickel chloride gas. In order to sufficiently carry out the reaction, the temperature at that time was set to 800 ° C or more, and it was set to 1453 ° C or less of the melting point of nickel. Considering the reaction rate and the durability of the chlorination furnace, it is practically preferably in the range of 900 ° C to 1100 ° C.

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 a reduction step, and is brought into contact with a reducing gas such as hydrogen to react. At this time, the nickel chloride gas can be appropriately diluted with an inert gas such as argon or 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 such as the particle size distribution of the metal powder generated in the reducing portion. 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 the temperature sufficient to complete the reaction, preferably not more than the melting point of nickel, and from the viewpoint of economy, 900 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 nickel powder subjected to the reduction reaction was formed in this manner, the produced nickel powder was cooled. At the time of cooling, in order to prevent generation of secondary particles caused by aggregation of primary particles of nickel which are generated and to obtain nickel powder having a desired particle diameter, it is desirable to terminate the reduction reaction by injecting an inert gas such as nitrogen gas. The airflow near °C is rapidly cooled to about 400~800 °C. Thereafter, the produced nickel powder is separated and recovered by, 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 method for producing nickel powder by spray pyrolysis a thermally decomposable nickel compound as a raw material, specifically, a nitrate, a sulfate, a hydroxy nitrate, a hydroxysulfate, a chloride, an ammonium complex, a phosphate, a carboxylate, an alkoxide, or the like One or two or more. A solution containing this nickel compound was sprayed to prepare fine droplets. As the solvent at this time, water, alcohol, acetone, ether or the like can be used. Further, the spraying method is carried out by a spraying method such as an ultrasonic wave or a double jet nozzle. In this manner, fine droplets are formed and heated at a high temperature to thermally decompose the metal compound to form a nickel powder. The heating temperature at this time is preferably higher than the temperature at which the specific nickel compound to be 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 for producing a nickel powder by a liquid phase method, an aqueous nickel solution containing nickel sulfate, nickel chloride or a nickel complex is added to an alkali metal hydroxide such as sodium hydroxide or the like to be contacted to form nickel hydroxide. Then, the nickel hydroxide is reduced with a reducing agent such as hydrazine to obtain a metallic nickel powder. The metal nickel powder produced in this manner is pulverized as needed 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。 The nickel powder obtained by the above method is preferably dispersed in a liquid phase and washed in order to remove residual raw materials. For example, under the specific conditions in which the pH and temperature are controlled, the nickel powder obtained by the above method is suspended in an aqueous solution of carbonic acid for treatment. By treating with a carbonate aqueous solution, impurities such as chlorine adhering to the surface of the nickel powder can be sufficiently removed, and oxides such as nickel oxide present on the surface of the nickel powder, hydroxides such as nickel hydroxide, and particles due to particles can be removed. The particles formed are separated from the surface by friction or the like, and a thin and uniform film containing nickel oxide and nickel hydroxide can be formed by using dissolved oxygen in the water. As a profit The method of treating the aqueous solution with carbonic acid may be a method of mixing a nickel powder and an aqueous solution of carbonic acid, or blowing carbon dioxide gas into a water slurry after temporarily washing the nickel powder with pure water, or adding an aqueous solution of carbonic acid to the temporary pure water. The water slurry after washing the nickel powder is treated.

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 of containing sulfur in the nickel powder of the present invention is not particularly limited, and for example, the following method can be employed.

(1)在上述還原反應中添加含硫氣體的方法 (1) A method of adding a 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) A method of contacting nickel powder with a sulfur-containing gas and performing treatment

(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 for 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) A method of adding a sulfur-containing compound solution to a slurry for dispersing nickel powder in a 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) A method of foaming a sulfur-containing gas in a slurry in which a 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。 In particular, from the viewpoint of being able to precisely control the sulfur content and uniformly adding sulfur, the methods (1) and (4) are preferred. The sulfur-containing gas used in the methods (1), (2), and (5) is not particularly limited, and a gas such as sulfur vapor, sulfur dioxide gas, or hydrogen sulfide gas which is a gas at a temperature of a reduction step can be directly used. Or use after dilution. Among them, sulfur dioxide gas and hydrogen sulfide gas are advantageous from the viewpoint that the gas is at a normal temperature and the flow rate is easily controlled, and the concern of mixing impurities is low.

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 the vulcanization step, the nickel powder slurry is dried. The drying method is not particularly limited, and a known method can be used. Specifically, it can be mentioned that it is brought into contact with a high-temperature gas. Drying is carried out by air drying, heating drying, vacuum drying, and the like. Among them, the air flow drying is preferred because the particles collide with each other without the destruction of the sulfur-containing layer.

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 in the above manner was subjected to an oxidation treatment under specific conditions. Specific examples of the oxidation treatment include an inert gas containing oxygen (nitrogen, argon, etc.) in a gas atmosphere containing an oxidizing gas (for example, oxygen or ozone gas) (for example, in a gas atmosphere of air or oxygen). A method of performing heat treatment in a gas atmosphere or the like). The optimum heat treatment temperature at this time varies depending on the particle diameter, and is preferably 140 to 180 ° C, and particularly, the average particle diameter of 140, which is an average particle diameter of 250 nm or less used in the production step of the laminated ceramic capacitor. For the case of ~250 nm, it is preferably maintained in the air at 160 to 180 ° C for 1 minute to 4 hours. In the analysis of the chemical bonding state of nickel in the surface layer of the nickel powder by X-ray photoelectron spectroscopy (XPS), the area ratio of the peak attributed to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 is 55.0~ 80.0%, the area ratio of the peak of the metallic nickel to the overall spectrum of the Ni2p _3/2 is 5.0 to 15.0%, and the heat treatment conditions (temperature, time) are adjusted and appropriately performed. In this manner, a stronger nickel oxide film can be formed by subjecting the nickel powder to oxidation treatment.

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 nickel powder and an organic solvent. Further, an organic binder such as ethyl cellulose, a dispersant, and an unfired powder of a ceramic to be coated may be contained as needed.

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。 The nickel paste can be added with the above nickel powder, an organic solvent such as terpineol, or an organic binder such as ethyl cellulose as needed. The agent, the dispersing agent, and the unfired powder of the ceramic to be applied are easily produced by a known method in which three rolls are kneaded. Examples of the organic solvent include alcohol, acetone, propanol, ethyl acetate, butyl acetate, ether, petroleum ether, mineral spirits, and other alkane hydrocarbon solvents, or butyl carbitol and terpineol. , dihydroterpineol, butyl carbitol acetate, dihydroterpineol acetate, dihydrocarvyl acetate, carvyl acetate, terpene acetate, An acetate ester such as linalyl acetate, a propionate solvent such as dihydrofurfuryl propionate, dihydrocarvyl propionate or isodecyl propionate, ethyl celecoxib, butyl raceway Sue and other types of Cyrus, aromatics, 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。 Further, as the organic binder, a resin binder is preferable, and examples thereof include ethyl cellulose, polyvinyl acetate, acrylic resin, alkyd resin, and the like.

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 the dispersing agent, a known suitable dispersing agent can be used, and for example, a vinyl polymer, a polycarboxylic acid amine salt, a polycarboxylic acid or the like 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 as described above has a film containing nickel oxide and nickel hydroxide having a certain thickness and density on the surface thereof, and thus exhibits excellent sintering behavior in the manufacturing step of the laminated ceramic capacitor. It can prevent the occurrence of delamination. More specifically, when the heat treatment is performed, it is a matter of course that the volume change or the weight change caused by the redox reaction is small, and the sintering start temperature is higher than that of the conventional nickel powder, so that it becomes closer to the manufacture of the laminated ceramic capacitor. The sintering start temperature of the dielectric used, as a result, can effectively prevent the occurrence of delamination.

[實施例] [Examples]

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。 The present invention will be further illustrated by the following examples and comparative examples, but this is merely illustrative and not restrictive.

[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 a gas phase reaction method in which nickel chloride and hydrogen are reacted, washing is carried out in pure water and an aqueous solution of carbonic acid, and a sulfur-containing compound is added to a slurry in which nickel powder is dispersed in a liquid phase, and dried to prepare nickel. powder. The spherical nickel powder having a number average particle diameter of the obtained nickel powder of 191 nm, an average aspect ratio of 1.2, and an average circularity coefficient of 0.68 was confirmed. Further, the specific surface area was 4.0 m ² /g, and the specific surface area was 168 nm. Further, 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 atmosphere to obtain a nickel powder. Oxygen content, average particle diameter, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of a film of nickel oxide and nickel hydroxide, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter, and The measurement results of 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.

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。 Further, when the nickel powder of Example 1 was subjected to infrared absorption spectrum analysis, an absorption peak due to the wave number of the OH group chemically bonded to the metallic nickel of 3600 to 3700 cm ^-1 was observed.

[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。 A sample was prepared in the same manner as in Example 1 except that the oxidation treatment was carried out at 155 ° C for 2 hours in an oxidizing gas atmosphere to obtain a nickel powder. Oxygen content, average particle diameter, X-ray photoelectron spectroscopy (XPS) measurement, dispersion evaluation, thickness of film of nickel oxide and nickel hydroxide, 2% heat The measurement results of the ratio of the shrinkage temperature, the specific surface area diameter, the number average particle diameter, and 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。 A sample was prepared in the same manner as in Example 1 except that the oxidation treatment was not carried out, and nickel powder was obtained. Oxygen content, average particle diameter, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of a film of nickel oxide and nickel hydroxide, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter, and The measurement results of 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。 A sample was prepared in the same manner as in Example 1 except that the oxidation treatment was carried out at 230 ° C for 2 hours in an oxidizing gas atmosphere to obtain a nickel powder. Oxygen content, average particle diameter, X-ray photoelectron spectroscopy (XPS) measurement, dispersibility evaluation, thickness of a film of nickel oxide and nickel hydroxide, 2% heat shrinkage temperature, specific surface area diameter, number average particle diameter, and The measurement results of 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.

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。 Hereinafter, the oxygen content, the average particle diameter of the nickel powder of each of the above Examples and Comparative Examples, and the ratio of the area of the metallic nickel to the surface oxide and the surface hydroxide by X-ray photoelectron spectroscopy (XPS) and the dispersibility are shown. The method for measuring the thickness of the coating film of nickel oxide and nickel hydroxide and the 2% heat shrinkage temperature was evaluated.

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 capsule made of nickel, placed in a graphite crucible, heated to 500 ° C in an argon atmosphere, and subjected to Fourier transform type red. The external spectrophotometer quantifies the carbon monoxide generated at this time, and determines 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 by an electron microscope, and the image analysis software was used for the photograph, and the particle diameter of 900 powders was measured, and the number average particle diameter was calculated. At this time, the particle diameter is the diameter of the smallest circle of the particles.

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

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。 The Ni2p _3/2 spectrum on the surface of the powder was measured using an X-ray photoelectron spectroscopy analyzer (K-ALPHA ⁺ manufactured by Thermo Fisher Scientific Co., Ltd.), and the spectrum was peaked using the analytical software "Avantage Ver. 5.951" attached to the analyzer. Separation, calculation of the area ratio of the peak of the metallic nickel to the overall spectrum of Ni2p _3/2 , the ratio of the peaks attributed to the bonding state of nickel and oxygen to the overall spectrum of Ni2p _3/2 , and the bond attributed to 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) Dispersion evaluation

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 placed in 100 g of pure water, and dispersed by an ultrasonic disperser (Sonic Technology Co., Ltd., GSD600AT) for 1 minute. After the dispersion treatment of the sample, the filter was filtered under reduced pressure using a membrane filter of 3 μm. If the total amount of the slurry passed through the membrane filter was within 30 seconds, it was good (○). In the case of more than 30 seconds, it is set to be defective (×).

5)氧化鎳及氫氧化鎳的被膜的厚度 5) Thickness of the 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 directly sprinkled on a copper mesh screen to which a fire-cotton film was attached, and then carbon was vapor-deposited to prepare a measurement sample. Next, using a transmission electron microscope (JEM-2100F, manufactured by JEOL Ltd.), it is accelerating The lattice image of the sample was observed under the conditions of a voltage of 200 kV, and the thickness of the film of nickel oxide and nickel hydroxide on the surface of the nickel powder was measured at six points to calculate the average.

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 mixed nickel powder, 3 wt% of camphor, and 3% by weight of acetone were filled in a cylindrical mold having 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. The test piece was measured under the conditions of a heating rate of 10 ° C/min in a gas atmosphere of nitrogen (containing 2% of hydrogen) using a dilatometry measuring apparatus (TMA, 8310, manufactured by Rigaku Co., Ltd.). . Further, the temperature of 2% heat shrinkage measured by the thermal expansion contraction behavior measuring device (TMA) was taken 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。 The specific surface area was measured by using a BET specific surface area measuring apparatus (manufactured by Mountech Co., Ltd.) under a nitrogen gas flow at 160 ° C for 1 hour, and the specific surface area S was calculated from the specific surface area S using the following formula (Formula 1). . Here, ρ is the true density of nickel. Further, the ratio of the number average particle diameter D to the specific surface diameter d is 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。 As is clear from Table 1, the nickel powder of Example 1 having a higher surface oxide ratio than the nickel powders of Comparative Examples 1 and 2 was superior in nickel powder of Comparative Example 3 in which the dispersion property was higher than that of the surface oxide. Therefore, since the nickel powder of the first embodiment is excellent in dispersibility, the mixing of the nickel powder and the common material is sufficient in the production of the laminated ceramic capacitor, 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。 Further, it is known that the film thickness of the nickel powder of Example 1 is larger than that 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。 Further, in terms of the 2% heat shrinkage temperature, the nickel powder of Example 1 was higher than the nickel powders of Comparative Examples 1 and 2, and further, in the sintering behavior of Fig. 1, there was no volume change at a 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 is estimated that the nickel powder of the present invention exhibits an excellent sintering behavior in the production step of the multilayer ceramic capacitor, and is excellent in dispersibility, and 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 described above, the nickel powder according to the present invention has a sintering behavior other than the conventional nickel powder in an average particle diameter of 250 nm or less. It is stable, and there is no shrinkage and swelling of the nickel powder in the low temperature region, and the dispersibility is excellent. Therefore, the paste using the nickel powder of the present invention can prevent the occurrence of delamination during the production process of the multilayer ceramic capacitor. 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, it is possible to provide a nickel powder which is very stable in sintering behavior, has no shrinkage and expansion of nickel powder in a low temperature region, and is excellent in dispersibility, and is 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 film containing nickel oxide and nickel hydroxide and having an average particle diameter of 250 nm or less, in the analysis of the chemical bonding state of nickel in the surface layer of the nickel powder by X-ray photoelectron spectroscopy (XPS) The area ratio of the peak attributed to the bonding state of nickel to oxygen to the overall spectrum of Ni2p _3/2 is 55.0 to 80.0%, and the area ratio of the peak of metallic nickel to the overall spectrum of Ni2p _3/2 is 5.0 to 15.0%, which is attributed to The area ratio of the peak of the bonding state of nickel to hydroxyl group 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.