摘要:
Sinterable Si.sub.3 N.sub.4 powder containing Si.sub.3 N.sub.4 particles and sintering additives wherein Si.sub.3 N.sub.4 particles have an average particle size of less than 1 .mu.m, contain no particle having a diameter greater than 100 .mu.m, have a total content of metallic impurities less than 1000 ppm and an iron content of less than 200 ppm, and wherein the sintering additives are uniformly distributed throughout the powder is prepared by co-grinding pulverulent sintering additive and Si.sub.3 N.sub.4 containing less than 1000 ppm metallic impurities in a spiral jet mill.
摘要翻译:含有Si 3 N 4颗粒的可烧结Si 3 N 4粉末和其中Si 3 N 4颗粒的平均粒度小于1μm的烧结助剂,不含直径大于100μm的颗粒,金属杂质的总含量小于1000ppm,铁 含量小于200ppm,并且其中烧结添加剂均匀分布在整个粉末中通过在螺旋喷射磨中共磨粉碎烧结添加剂和含有小于1000ppm金属杂质的Si 3 N 4来制备。
摘要:
Sinterable Si.sub.3 N.sub.4 powder having an average particle size of less than 1 .mu.m, wherein no individual particle has a diameter greater than 100 .mu.m, the total content of metallic impurities of the powder is less than 1000 ppm and the iron content is less than 200 ppm is produced by grinding agglomerated Si.sub.3 N.sub.4 in a spiral jet mill.
摘要翻译:平均粒径小于1μm的可烧结Si 3 N 4粉末,其中没有单个颗粒的直径大于100μm,粉末的金属杂质的总含量小于1000ppm,铁含量小于200 ppm通过在螺旋喷射磨中研磨附聚的Si 3 N 4来生产。
摘要:
Si.sub.3 N.sub.4 powder wherein the total oxygen content of the powder is 0.4% by weight or less is produced by preparing an amorphous Si.sub.3 N.sub.4 intermediate by reacting a Si-containing compound with an N-containing compound and the intermediate is then crystallized wherein "P", multiplication product of(i) the specific surface of the amorphous intermediate (BET in m.sup.2 /g),(ii) the moisture content C.sub.H.sbsb.2.sub.O (in volume ppm) of the atmosphere during handling and(iii) the time t in hours required for handling the amorphous intermediate,is kept smaller than the limit value product P.sub.G of 1000 in accordance with the following equation:"P"=BET (m.sup.2 /g).times.C.sub.H.sbsb.2.sub.O (vol ppm).times.t(h)
摘要:
Si.sub.3 N.sub.4 powders having a total oxygen content of less than 1.8% by weight with the proportion of surface oxygen content of more than 65% of the total oxygen content, and having a fluorine content of less than 35 ppm are prepared by annealing Si.sub.3 N.sub.4 powders having a total oxygen content of less than or equal to 0.4% by weight in an oxygen-containing atmosphere at temperatures of 700.degree. C. to 1200.degree. C. for 15 to 90 minutes or by grinding Si.sub.3 N.sub.4 powders having a total oxygen content of less than or equal to 0.4% by weight in water, alcohol or aqueous alcohol 15 to 120 minutes.
摘要翻译:总氧含量小于1.8重量%,表面氧含量占总氧含量的65%以上,氟含量小于35ppm的Si 3 N 4粉末是通过退火具有 在含氧气氛中,在700℃至1200℃的温度下,总氧含量小于或等于0.4重量%,持续15至90分钟,或通过研磨总氧含量低于或等于或等于或等于0的Si 3 N 4粉末, 在水,醇或含水醇中等于0.4重量%至15分钟至120分钟。
摘要:
Silicon nitride powder having a total oxygen content of less than 1.8% by weight and an isoelectric point in 0.001M aqueous KNO.sub.3 solution of below pH 4 is prepared by calcining Si.sub.3 N.sub.4 powder having an oxygen content of 0.4% by weight or less in an oxygen containing atmosphere at temperatures between 700.degree. and 1200.degree. C. for 15 to 90 minutes or by grinding such as Si.sub.3 N.sub.4 powder in water, lower alcohol or a water/alcohol mixture for 15 to 120 minutes.
摘要翻译:通过在氧含量为0.4重量%以下氧化氧含量为0.4重量%以下的Si 3 N 4粉末,制备总氧含量小于1.8重量%的含有低于pH 4的0.001M KNO 3水溶液中的等电点的氮化硅粉末 气温在700〜1200℃的温度下浸渍15〜90分钟,或者研磨如Si3N4粉末在水,低级醇或水/醇混合物中15〜120分钟。
摘要:
Carbides, nitrides or carbonitrides of elements from the main groups III and IV and sub-groups III, IV, V and VI of the periodic system of elements are prepared by(i) reacting compounds of the formula MX.sub.m or R.sub.n MX.sub.m-n with a reactive hydrocarbon-containing compound or a mixture of compounds which is polymerizable and which contains a reactive compound with one C--OH-group in whichM is an element of the main group III or IV or sub-group of III, IV, V or VI of the periodic system of elements,X is a halogen,R is hydrogen or alkyl or aryl,m is an integer corresponding to the valency stage of M,n is an integer from 1 to one less than the velency stage of M, and(ii) thermally decomposing the resulting product from (i) to the corresponding carbide or to the corresponding nitrides or carbonitrides with further nitridation.
摘要:
A process for preparing finely-divided oxides of metals of metalloids of the elements of main groups III and IV and sub-groups III, IV, V and VI of the Periodic System of Elements, comprising reacting compounds of these elements with a polymerizable hydrocarbon compound or mixture to form a polymer product, which is then thermally treated to yield the oxide product.
摘要:
The invention relates to a reducing agent for the soluble chromate content of cement and to methods for the production thereof, which comprise concentrating an used sulfuric acid, containing iron(II) sulfate, and separating the sulfuric acid from the obtained precipitate which contains iron(II) sulfate.
摘要:
The invention relates to a reducing agent for the soluble chromate content of cement and to methods for the production thereof, which comprise concentrating an used sulfuric acid, containing iron (II) sulfate, and separating the sulfuric acid from the obtained precipitate which contains iron (II) sulfate.
摘要:
The invention concerns a method for processing heavy metal-laden spent sulfuric acid. For this, iron-laden spent sulfuric acid or iron-laden sulfuric materials obtained therefrom are reacted with a material that contains iron chloride and optionally other metal chlorides, producing iron (II) sulfate. The spent sulfuric acid preferably derives from titanium dioxide production.