PURPOSE: To obtain a sliding material causing no increase in the frictional resistance at high temp. by adding a specified amount of an inorg. solid lubricant to a martensitic steel contg. a specified amount of Cr as a base material.

CONSTITUTION: Metallic particles of a steel contg. 5W14wt% Cr are mixed with powder of an inorg. solid lubricant such as carbon or boron nitride, and the mixture is sintered at about 1,100W1,300°C and formed into a platelike shape to obtain a sliding material. At this time, the upper limit of the amount of the lubricant added is regulated to 15vol% in consideration of the strength of the sintered body, and the lower limit is regulated to 5vol% in consideration of the lubricating performance. The resulting sliding material enables the free thermal expansion and contraction of each support of various heat transfer devices such as the superheater and evaporator of an exhaust gas boiler when the operation of the boiler is started and suspended, so stress due to friction between the support and its support holder is not produced.