nitride layer formed by cvd and a titanium based oxide layer formed by cvd the hardened layer comprising a nitride layer having a thickness of at least 0 05 mm and preferably at least 0 2 mm the alloy according to the invention surpasses comparably usable alloys according to the prior art not only in terms of the mechanical strength at temperatures above 700 u00b0 c and as high as 1000 to 1050 u00b0 c but also in terms of thermal shock resistance the alloy according to the invention can therefore be used particularly advantageously as a material for components of thermal installations which at temperatures of at least 700 u00b0 c to 800 u00b0 c and still have a relatively high mechanical strength and which like gas turbine casings are subject to strong thermal cyclic loading a nozzle ring was manufactured using standard techniques except that the alloy used was the alloy according to the present invention having the following composition with all percentages being weight percent of the total alloy the alloy 46 50 hrc was solution annealed 1 h at 1150 1180 u00b0 c then hardened for 2 h at 700 u00b0 c the product had the following characteristics grain structure duplex steel with very very fine grain with 3 4 phases in the matrix tribologically very good hardness 32 35 hrc thermal coefficient of expansion alpha value less than 15 u00d7 10 u2212 6 dynamic test 1500 hours under performance at 100 of nominal value of a commercial truck without problems test 2 7 hour at 1000 u00b0 c pascar range and nozzle ring appeared new no detectable mechanical distortion brake test iveco eurotech engine test cell arbon ch u2014 satisfactory less particulate the.