A protective and abradable coating composition is suitable for application on rolls and more particularly for application on conveyor rolls. The abradable coating is suitable for use in high temperature applications. Rolls incorporating the coating may be produced and used according to disclosed processes and procedures. Application of the composition to rolls reduces corrosion by aluminium melt, and enables the removal of built-up substances by friction. The life time of the roll is thereby increased.

A protective and abradable coating composition is suitable for application on rolls and more particularly for application on conveyor rolls. The abradable coating is suitable for use in high temperature applications. Rolls incorporating the coating may be produced and used according to disclosed processes and procedures. Application of the composition to rolls reduces corrosion by aluminium melt, and enables the removal of built-up substances by friction. The life time of the roll is thereby increased.

PURPOSE: To provide a method capable of detecting a large oxygen deposit existing in a silicon single crystal obtained by a CZ method with good sensitivity.

CONSTITUTION: A silicon single crystal is subjected to heat treatment for 30 to 300 minutes at 900 to 1050 deg.C in a dry O2 atmosphere, then, is subjected to heat treatment for 30 to 200 minutes at 1100 to 1200 deg.C in a wet O2 atmosphere. After this crystal is treated with a dilute hydrofluoric acid and an oxide film on the surface of the crystal is removed, the crystal is dipped in a seco solution for 1 to 30 minutes to etch selectively the face <100> and lastly, the number of pieces of OSFs, which appear on the silicon single crystal surface, is found by an optical microscope. Accordingly, by this two-stage heat treatment, as a large oxygen deposit in the crystal is turned into the selective OSFs and the OSFs appear on the crystal surface, an inspection of the quality of the silicon single crystal can be carried out with high sensitivity.

PURPOSE: To provide a method capable of detecting a large oxygen deposit existing in a silicon single crystal obtained by a CZ method with good sensitivity.

CONSTITUTION: A silicon single crystal is subjected to heat treatment for 30 to 300 minutes at 900 to 1050 deg.C in a dry O2 atmosphere, then, is subjected to heat treatment for 30 to 200 minutes at 1100 to 1200 deg.C in a wet O2 atmosphere. After this crystal is treated with a dilute hydrofluoric acid and an oxide film on the surface of the crystal is removed, the crystal is dipped in a seco solution for 1 to 30 minutes to etch selectively the face <100> and lastly, the number of pieces of OSFs, which appear on the silicon single crystal surface, is found by an optical microscope. Accordingly, by this two-stage heat treatment, as a large oxygen deposit in the crystal is turned into the selective OSFs and the OSFs appear on the crystal surface, an inspection of the quality of the silicon single crystal can be carried out with high sensitivity.

A new class of multi-component rare earth multi-silicate materials has been created for use in harsh environments such as gas turbine engines. Moreover, by combining two-or-more rare earth disilicates the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications, such as having a matching thermal expansion with that of silicon-based composites and a low thermal conductivity close to that of 1 W/m K. Applications can be extended for use with other material classes such as MCrAlY, MAX-phase, and refractory metal alloys, utilizing a thermal expansion of up to about 1510.sup.6/ C. By mixing of specific sets of rare earth disilicates it is possible to obtain a high entropy or entropy stabilized mixture, and utilize features such as sluggish diffusion, and more.

A new class of multi-component rare earth multi-silicate materials has been created for use in harsh environments such as gas turbine engines. Moreover, by combining two-or-more rare earth disilicates the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications, such as having a matching thermal expansion with that of silicon-based composites and a low thermal conductivity close to that of 1 W/m K. Applications can be extended for use with other material classes such as MCrAlY, MAX-phase, and refractory metal alloys, utilizing a thermal expansion of up to about 1510.sup.6/ C. By mixing of specific sets of rare earth disilicates it is possible to obtain a high entropy or entropy stabilized mixture, and utilize features such as sluggish diffusion, and more.