摘要:
A device including an injection molding tool for use once or a few times for producing a sinterable ceramic and/or metallic product. The device includes at least one first tool part. At least one second tool part is combinable with the at least one first tool part to form a molding space for the product. The second tool part is produced using a wet composition and is made of a readily worked and form-stable material containing pores and admixed heat-conducting particles. A wet composition-enclosing member can engage the first tool part during the production of the second tool part. A unit can be connected to the at least one second tool part and can be arranged with the at least one first tool part for absorbing internal lateral displacement forces arising during squeezing or injection of an injection molding composition. The injection molding tool is adapted to receive an injection molding composition containing a ceramic and/or metallic powder that is introduced into the molding tool with low or medium pressure for forming the product. The pores and the admixed heat-conducting particles conduct away heat generated during the molding and gas trapped in the molding space. The pores also provide a well-balanced porosity for effecting conduction of the gas and, together with a flexibility in the solidified injection molding composition, permit the product to be separated from the tool parts without braking.
摘要:
A new group of ceramic composite materials containing silicon oxynitride (Si.sub.2 N.sub.2 O, O'-phase) and zirconium oxide (ZrO.sub.2) can be prepared using a thermal reaction between zirconium silicate (ZrSiO.sub.4) and silicon nitride powder (Si.sub.3 N.sub.4) supplied completely or partly as silicon powder (Si) which is nitrided to Si.sub.3 N.sub.4 in a nitrogen-containing atmosphere. By adding aluminium oxide or the like, composite compositions with ZrO.sub.2, O'-phase and sialons (silicon aluminium oxynitrides) as main components can be obtained. In the method according to this invention, the raw powder material is prepared, e.g. by concurrent milling and blending to submicron particle size, formed by known technique into a compact, nitrided and sintered to the desired density in nitrogen-containing atmosphere.
摘要翻译:PCT No.PCT / SE88 / 00296 Sec。 371日期:一九八九年十一月十六日 102(e)日期1989年11月16日PCT提交1988年5月31日PCT公布。 出版物WO88 / 09778 日期:1988年12月15日。可以使用硅酸锆(ZrSiO 4)和氮化硅粉末(Si 3 N 4)之间的热反应制备新的含氮氧化硅(Si 2 N 2 O,O相)和氧化锆(ZrO 2)的陶瓷复合材料 )完全或部分提供为在含氮气氛中氮化为Si 3 N 4的硅粉末(Si)。 通过添加氧化铝等,可以获得作为主要成分的具有ZrO 2,O相和硅铝氧氮(硅铝氧氮化物)的复合组合物。 在根据本发明的方法中,制备原料粉末。 通过将通过已知技术形成的亚微米尺寸的同时研磨和共混成为在含氮气氛中的压实,氮化和烧结至所需密度。
摘要:
The present invention belongs to the field of technology known as powder injection moulding. It includes producing a part by powder injection moulding at low to high injection pressure and it discloses a novel binder system for optimized feedstock design. The primary subject matter of the invention resides in introducing a secondary main binder into the feedstock binder composition, meeting, simultaneously, the five (5) following criteria: partially soluble in the primary binder, soluble in water, thermally evaporable, possessing a dispersant functionality and increasing the viscosity at near zero feedstock shear rate. In addition to this binder, the feedstock may contain a small fraction of another dispersant and a back-bone polymer when needed, depending on the type of powder material used for the feedstock. Based on the main modes of binder removal (thermal or water extraction) this novel binder system is denominated as Te-Wex™ system. Using this binder concept feedstocks with a wide variety of powders, including alumina, zirconia, silicon nitride, stainless steel and low-alloyed steel could be prepared and subsequently injected using the MPIM (Medium pressure Powder Injection Moulding) technique into one- or multiple cavity tools to make parts of variable thickness. These parts could be debinded either by partial water extraction and/or thermal evaporation and sintered to final density of over 99 vol % of the respective theoretical values.
摘要:
Process for the production of moulded bodies of materials based on silicon nitride, where the powder mix prepared by way of initial material contains silicon nitride (Si.sub.3 N.sub.4), a high proportion, preferably 40-85 percent by weight, of silicon (Si) and a sintering aid. With conventional sintering the above powder mix is advantageously prepared by grinding of an Si-powder dispersed in an Si.sub.3 N.sub.4 powder the grain size of which is considerably lower than that of the Si-powder. The process covers in the main the production of a body moulded from this powder mix by known moulding methods, nitriding of the Si-content to Si.sub.3 N.sub.4 and sintering of the moulded body to a final required density.