Application of transparent sintered alumina

 From, recently, the China Nonferrous Metals website reported that the light of the same power halogen plasma lamp is clearer and brighter than the traditional incandescent bulb. If they can increase their internal pressure, they will be more efficient and have a longer life. However, this is limited by the high temperature resistance of materials used to manufacture electron beam tubes and bulbs. The conventionally used quartz glass and ceramic materials are too soft to accommodate the high pressure inside the bulb and may even cause the lamp to explode. One material that can withstand such high temperatures is alumina, also known as alumina or corundum. Pure corundum, like its natural shape of sapphires and rubies, does not melt below 2000 °C. However, powdered silicon carbide is difficult to melt by a conventional glass manufacturing process, and is blown and cast into a shape because crystals are formed when the melt solidifies. Therefore, the current production process is to control the temperature below 2000 ° C below the melting point, at which small particles are sintered and mixed together on the surface while increasing in speed. Small particles and pores between them can transmit light. These widely used high-efficiency ceramic materials are milky white, just like opal glass. The new aluminas currently being developed are almost transparent and have twice the hardness. Scientists have successfully made alumina ceramics in a variety of shapes. In addition to being used to make hollow bulbs, it can also be used as a window for anti-scratches or special optical instruments on scanners. The key factor in achieving transparency is that the particle size of the raw materials is less than 1/3 micron, and in the finished product, the particle size of the particles cannot exceed 1/2 micron, so they hardly diffuse any light. The new manufacturing process is 600°C cooler than conventional processes. In addition, the formation and sintering process of the ceramic material also affects the size and porosity of the particles. The material is being further refined and the finished product has almost no porosity and is very strong enough to be used in the manufacture of new luminaires. Editor: Zheng Yaqin 2005-8-13 China Lighting Network