“After leaving Hungary in 1922, the tin job having been accomplished successfully, I associated for a short time with a small foundry in Baden-Baden, Germany, where I set up the rudiments of a research laboratory. The first experiments in this place were quite successful. They concerned the creation of a low expansion piston alloy with good wear resistance, good creep strength and light weight. I developed there the hyper-eutectic 23% Si- Al alloys with small additions of copper, sold later for many years as “Alusil”in Germany and as “Alsia”in France. Favourable circumstances permitted the production of this alloy since it was brought out just at the right moment when sintered carbide tools made possible the machining of grooves in pistons cast of this hard alloy.”
Kroll filed corresponding patent applications at the beginning of 1924.
“Later I found that zinc also can be used to deantimonise solder providing any copper present is entirely removed before the operation. This process was used commercially for sometime.”
“A substitution of titanium or aluminum for beryllium in nickel-bearing steels was also found to impart considerable age-hardenability.”