1. Field of the Invention
The present invention relates generally to the manufacture of refractory materials, and more specifically to the composition of thermally-resistant ceramics-based product and coating materials, both for use in high-temperature structures and other applications, including metallic molds, building blocks, and structural members that are exposed to the high temperatures.
2. Description of the Prior Art
A structural product that is shaped or formed so that it can resist the high temperature when it is exposed in such high temperature environment is known to the prior art. For example, a refractory brick is used for forming the interior walls of the furnace. In this application, the refractory brick becomes more brittle as the ambient temperature is rising to a higher temperature (such as 1,200.degree. C. or more), and tends to break or fuse easily when any external force is applied under the high temperature conditions. Thus, demand arises for other products that can have a mechanical and/or chemical strength sufficient to resist both the high temperature and external forces. Furthermore, there is no means that can effectively protect metal parts from any corrosion that may be produced when they are placed under the high temperature environment, are heated to high temperatures, or are exposed to burning gases. In this case, demand also arises for coating materials that can resist in those situations. In either case, no successful products or materials have been known.
As described, the conventional refractory brick tends to break easily as the ambient temperature rises above 1,200.degree. C. and if any external force is applied, causing severe damage and wear. Other refractories are also known, which tend to have their original shaped altered easily when they are in the fusible state or any external force is applied. Those materials may be used as coating materials, but are not suitable for some particular applications which require mechanical strength and high-temperature resistance, such as furnaces and aerospace craft (such as recoverable capsules in particular). Other refractory products that are used for some special purposes are obtained by the special manufacturing process (such as high-pressure, high-temperature treatment). When the shapes become more complicated, it is difficult to obtain those shapes with high precision. Therefore, those complicated shapes can only be obtained at high cost. Particularly, for those products that require the higher temperature resistance, the manufacturing costs tend to increase remarkably.
Some metal molds allow any particular shapes to be produced by using the high-temperature burning gases. It is known that when the surface temperature of the metal mold rises to between 750.degree. C. and 1,200.degree. C., its metal parts will become oxidized by the heat produced, or corrosion may be caused by the burning gases. However, no effective means is provided for preventing those adverse effects.
Other metal molds are used to press and squeeze a product into a particular shape. During the squeezing process, the temperature rises rapidly to between 150.degree. C. and 1,200.degree. C., which may burn out the metal parts.
A temperature sensor or thermometer that is used for measuring the internal temperatures inside the furnace is enclosed in its protective casing. This protective casing is exposed to the high-temperature heating produced in the furnace, and may become eroded prematurely under those severe conditions. Thus, those protective casings may soon become useless, and must be replaced more frequently or at relatively short-term intervals.