As an inorganic non-metallic material that has been used earlier, alumina has lower specific gravity and good high-temperature stability, better wear resistance, corrosion resistance, high temperature resistance and electrical insulation properties. It can be used as abrasives, abrasives, tools , Bearings, nozzles, vacuum devices, circuit boards and bioceramics. For example, Pt-Rh thermocouple protection tube, platinum wire resistance thermometer protection tube, pressing and forging profiles, rocket nozzle, crucible, pure metal manganese distillation device, electronic tube tungsten wire support frame, metal wire drawing die, synthetic fiber guide wheel , Mud water pump collar, ball ball of ball mill, wet cyclone nozzle, spark plug, etc. 99 alumina ceramic substrate or 99 alumina ceramic structural parts usually need to be sintered at a higher sintering temperature (≥ 1750 ℃). Due to the extremely high sintering temperature, which exceeds the limit service temperature (1680 ℃) of ordinary continuous electric tunnel kilns, the existing continuous electric tunnel kilns cannot meet the requirements of sintering, and intermittent hydrogen atmosphere furnace or traditional hot-press sintering furnace must be Atmospheric furnaces or hot-press sintering methods require high equipment, low output, and high cost. Excessively high sintering temperature, in addition to high energy cost consumption, kiln and kiln furniture loss is large.
Patent Announcement No. CN1533999, published on 20041006 "99 alumina ceramics sintered at low temperature and its manufacturing method and use", two or three of Y2O3, ZrO2, and MgO are mixed to form a sintering agent to reduce the sintering of 99 alumina ceramics Temperature, but the patent does not mention that Li2O can be used as a sintering aid for 99 alumina ceramics. The paper "Summary of Research on Alumina Ceramic Sintering Aids" (Jiangsu Ceramics, 2012 (8) 20-23) mentioned that alumina ceramics sintering aids can be divided into single-phase sintering aids, binary sintering aids, and ternary and quaternary Yuan, quinary sintering aid system, including single-phase sintering aids Ti, Nb, Co, Ge, Mn, Ca, Y, Tb, Ce, Zr, Co, but did not mention that Li2O can be used as 99 alumina ceramics Sintering aid. Patent Publication No. CN102627447A, publication date 20120808 "A method for quickly sintering high-conductivity alumina-based transparent ceramics at low temperature by hot pressing" discloses a method for preparing high heat by using spark plasma sintering method using silica and lithium carbonate as sintering aids Conductivity alumina-based transparent ceramic method. Patent Announcement No. CN101654366A, publication date 20100224, "Composite Baking Aids and Methods for Low-Temperature Nanocrystalline Ceramics" discloses sintering aids including Lu, Na, Ca, In, Mg, Fe, Co, Ni, Cu, Zn, Bi, using at least two sintering aids, is suitable for CeO2, ZrO2 nanocrystalline ceramics doped with binary or ternary.
A method for reducing the sintering temperature of 99 alumina ceramics, the method is as follows: Weigh 99 to 99.9 parts of alumina and 0.1 to 1 part of lithium oxide according to the mass parts, add the alumina and lithium oxide to the ball mill, and pour into distilled water Or absolute ethanol as the solvent, the mass ratio of the solvent to alumina and lithium oxide is 3 ~ 10: 1, ball milling 0.5 ~ 24 h, and then drying in the oven for 0.5 ~ 12 h, the drying temperature is 80 ℃ ~ 200 ℃ , The dried powder is put into a metal mold, pressed into strips or discs under 100-300 MPa, heated at 0.5 ~ 3 ℃ / min, heated to 1350 ℃ ~ 1550 ℃, and kept at this temperature for 1 ~ 3 h for sintering to obtain dense 99 alumina ceramics.
What is the method and process of 99 alumina ceramic sintering temperature?
2020 05/18