I have seen stainless steel used as battery contacts. The contacts developed an oxide on them that made it difficult to get power from the battery. Seems to me that some plating could solve that problem however.
There are no good substitues for BeO in all applications. AlN is better than alumina, but not as good as BeO. If the application needs a simple flat insulator to conduct heat, and is small, diamond is a wonderful material - better heat conductivity than copper! Don Borowski Schweitzer Engineering Labs Pullman, WA Fred Townsend <[email protected]>@majordomo.ieee.org on 01/31/2003 12:38:19 AM Please respond to Fred Townsend <[email protected]> Sent by: [email protected] To: Jan Vercammen <[email protected]> cc: [email protected] Subject: Re: BeCu problem I can't help you with the regulations but I can clarify the usage of Beryllium a bit. When Beryllium is added to copper it makes it very hard. It is used in gaskets to make them springy. Stainless steel is a poor substitute because it lacks both the electrical and thermal conductivity. So far as I know there is no handling hazard unless you saw or grind it. Beryllium oxide BeO has similar restrictions on grinding. I don't know if it can be sawed. It would probably take a diamond blade in a liquid bath to have a chance at sawing. BeO has seven times better thermal conductivity than AlO (alumina). There is no real substitute for BeO at high power levels. It is still used by the Military in high power radar applications such as tubes. Fred Townsend Jan Vercammen wrote: > Hello EMC/PSTC-list, > > I have a question concerning Berylium Copper (BeCu). Even though this is > not a direct > EMC oriented question, it is or could be, indirectly, a serious problem in > the EMC shielding of our > products. > > I have been asked if BeCu can still be used in Europe and the USA (and the > rest-of-the world) as > the material for shielding gaskets and fingers. > > The main issue here is that Berylium (probably in combination) is > classified as an carcinogen and > it is also know to cause lung diseases (e.g. CDB or chronic Berylium > disease). Note that this is only the > case if small particles are inhaled into the lungs. However, I have also > received conflicting information > that it is BeO (Berylium Oxide) which is or could be the cultprit. BeO is > used as an electronic packaging material. > > Therefore I assume that the BeCu gaskets and fingers are not an health > hazard when used as a > shielding part in our products, but are (or could be) hazardeous during > manufacturing and recycling. > > I have been told on several occasions that BeCu is not allowed any more, > but one can not provide > me with standards or legal texts to substantiate the above statements. I > have also been told that > we need to change the BeCu shielding parts asap to stainless steel parts. > However, personally > I do not feel convinced and was hoping that EMC experts on the > EMC/PSTC-list could help me out with the > following questions: > > -1- is it correct that BeCu fingers/gaskets are considered a hazardeous > substance and that they will > be abolished from electronic equipment? > -2- if question 1 is correct, what is then the exact argument for not > using BeCu?? > -3- are there (world wide) legal standards/regulations published that state > that BeCu (as a finished product) > cannot be used anymore and by which date??? > -4- what is your experience with the conversion of BeCu to stailess steel > gaskets/fingers for non-dynamical > shielding applications (cost, problems, ...)??? > > Kind regards, > > Jan Vercammen > Agfa-Gevaert NV > Mortsel, Belgium This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
