Oh Kinser!- you just triggered an automatic story from my old brain with the term "Hydrogen embrittlement" Many years ago they had a big photo op with the Governor of Iowa driving off in a new Chrysler with one of the first catalytic converters. He went barreling down an old road between the large dry cornfields while everyone clapped. Then the car backfired, and the exploding gas blew the converter into hot parts that caught both sides of the road on fire. Luckily no one was injured. Every company that had a part on that car got it back to do testing on to see if they were the problem. Everyone sent back a report that they were not the problem. And at the time, I was sure I wasn't the problem either- the ignition device I made worked just fine. The converter had other problems that kept the cornfield fire off the radar, but as the months went by with no obvious cause we were all asked to study the problem again. I put the part through some military type vibration testing and oops- the device was intermittent. As soon as the part was still, it passed any test- but if it got a shake just right, it would go open for a while and then start to work again. Just like turning off the engine, coasting a bit and turning it back on to get a nice backfire ( we are talking 1975 or so). The metalization on the semiconductor had layers of titanium, tungsten, and nickle. They found hydrogen embrittlement in the layers causing them to give up adhesion and go intermittent. ( and probably caused the backfire) We had to put in a super hard test for adhesion { Duck Tape- I kid you not}, and we scrapped out the contaminated metal slugs we used. I took them all home and later used the tungsten to put in our first car in 1976. When we asked if turning off the ignition, coasting and then turning it back on would blow it up, They were sure it would even it it never came back on because if a chug of gas got into that 900 degree converter- trouble. Back to the drawing board for them also.
