摘要:
A process for the production of fine powder of metallic nickel which comprises a first step of dissolving nickel carbonate and/or nickel hydroxide in aqueous ammonia or in an aqueous solution of ammonia and at least one selected from the group consisting of ammonium carbonate, ammonium hydrogencarbonate, a carbonate of an alkali metal and a hydrogencarbonate of an alkali metal to prepare an aqueous solution of a nickel salt; converting the aqueous solution of a nickel salt to a W/O emulsion, and then removing volatile components including ammonia from the droplets to form precipitates of nickel carbonate in the droplets, thereby providing fine spherical particles of nickel carbonate; and a second step of heating the particles of nickel carbonate in the presence of a fusion preventive agent that is a compound of at least one element selected from the group consisting of alkaline earth elements, aluminum, silicon and rare earth elements in an atmosphere of hydrogen, thereby reducing the nickel carbonate to metallic nickel.
摘要:
The invention provides a process for production of fine spherical particles of a carbonate or a hydroxide of nickel, cobalt or copper which comprises: dissolving a carbonate or a hydroxide of nickel, cobalt or copper having the general formula (I) M(CO3)x/2.(OH)y wherein M represents Ni, Co or Cu, and x and y are numerals satisfying the followings: 0≦x≦2, 0≦y≦2 and x+y=2, in aqueous ammonia, converting the resulting solution to a W/O emulsion containing droplets of the solution in a non-aqueous medium, and then removing volatile components including ammonia from within the droplets, thereby precipitating a basic carbonate or a hydroxide of a metal selected from nickel, cobalt and copperin the droplets. The fine spherical particles of a carbonate or a hydroxide of nickel, cobalt or copper obtained according to the process of the invention are especially useful as a precursor for the manufacture of uniform, fine spherical particles of nickel, copper or cobalt metal, as well as useful as themselves as a catalyst for use in organic synthesis, a carrier, a pigment, a filler or a glaze.
摘要翻译:本发明提供一种生产镍,钴或铜的碳酸盐或氢氧化物的细球形颗粒的方法,其包括:将通式(I)的其中M表示Ni的镍,钴或铜的碳酸盐或氢氧化物溶解, Co或Cu,x和y是在氨水中将满足以下条件的数字:0 <= x <= 2,0 <= y <= 2和x + y = 2,将所得溶液转化成W / O乳液 在非水介质中含有溶液的液滴,然后从液滴内除去包括氨的挥发性组分,从而沉淀出液滴中选自镍,钴和铜的金属的碱性碳酸盐或氢氧化物。微球形颗粒 根据本发明的方法获得的镍,钴或铜的碳酸盐或氢氧化物特别可用作制造镍,铜或钴金属的均匀的细小球形颗粒的前体,并且作为其自身可用作 用于有机合成的催化剂,载体,颜料,填料或釉料。
摘要:
A multilayer piezoelectric composite comprising a bonded laminate each layer of which is composed of a green sheet of a low-temperature sintering lead zirconate titanate piezoelectric ceramic. The temperature coefficient of a frequency constant of at least one layer has a polarity opposite to the polarity of those of the other layers. The bonded laminate is sintered at a temperature which does not produce any or almost any interdiffusion between layers so that the absolute value of the temperature coefficient of a frequency constant of the bonded laminate is smaller than the absolute value of the temperature coefficient of a frequency constant of any or one of the layers.
摘要:
Single crystalline, ferrite particles are obtained by the thermal reaction of ferric oxyhydroxide, ferric hydroxide, porous ferric oxide made therefrom or ferric oxide having a particle size less than 0.8.mu. with a strontium or barium compound such as the oxide, hydroxide, the carbonate or the carboxylate in the presence of a small amount of a metal chloride flux such as strontium chloride or barium chloride.The resulting particles have a well-defined, hexagonal plate configuration and are particularly adapted for the production of anisotropic magnets.
摘要:
A method of producing single crystalline, acicular .alpha.-ferric oxide particles of narrow particle size distribution is provided. The method comprises heating an aqueous suspension of ferric hydroxide at temperatures of 100.degree.-250.degree. C. at an alkaline pH in the presence both a water soluble organic or inorganic compound capable of forming complexes with iron as a growth regulating agent and .alpha.-ferric oxide seed crystals of minor axes not larger than 0.4 microns in average in amounts of 0.1-25 mole % in terms of the Fe content thereof in relation to the ferric hydroxide.
摘要:
Single crystalline ferrite particles are obtained by the thermal reaction of ferric oxyhydroxide, ferric hydroxide, porous ferric oxide made therefrom or ferric oxide having a particle size less than 0.8.mu. with a strontium or barium compound such as the oxide hydroxide, the carbonate or the carboxylate in the presence of a small amount of a metal chloride flux such as strontium chloride or barium chloride.The resulting particles have a well-defined, hexagonal plate configuration and are particularly adapted for the production of anisotropic magnets.
摘要:
Single crystalline, acicular ferric oxide particles are produced by maintaining an aqueous suspension of ferric hydroxide at an elevated temperature at an alkaline pH in the presence of an organic phosphonic acid compound or a hydroxycarboxylic acid compound as a growth-regulating agent.