Diamond Turned Super Alloy Mandrel for Slump Forming X-Ray Observatory (IXO) Mirrors

Diamond turning is proven to be able to quickly produce highly aspheric grazing incidence optical contours to visible wavelength tolerances with extremely smooth surfaces.Super alloys with exceptional dimensional stability and strength under cyclic high temperatures have been developed for gas turbine engines. The thermal expansion can be in the range of the expansion of the borosilicate glasses used for X-Ray mirrors.This proposal utilizes an existing manufacturing learning curve to develop a reliable material and manufacturing process for glass slumping mandrels. This development process will involve the following investigations and development goals :-develop electroless nickel plating processes for super alloys,-ultra precision machining and polishability of super alloys.-diamond turning of electroless nickel before and after the slumping heat cycle.-heat treatment for dimensional stability under thermal cycling.-evaluation of oxidation of directly polished super alloys.-evaluation of oxidation of polished electroless nickel.Heat treatment and plating processes will be evaluated by producing a number of flat test mirror samples which will be measured optically before and after the glass slumping process to evaluate contour distortion, oxidation resistance, increase in surface roughness, and diamond machineability of the electroless nickel plating. A test slumping mandrel will be designed for fabrication in a Phase II SBIR.