ACCELERATED TESTING OF HIGH RELIABILITY PARTS. VOLUME 2
T. Walsh, G. Best
The parts under study were originally purchased for a reliaility evaluation program during Project Advent (Contract AF04(647)-476). the reliability test and evaluation portion of the 1-1 project was 1i'rlttatted inA 1960 to determine xnd speify peocurewint methods, screaening tec~hniquea, and test and eialtastion r,'o!7rsns which would provide asturaznce that the hardware for the flyable satollites wvu~ _t Ow prcgron objeotive of a 3-yea" life tr. a nunmaintaine'b1"o space er~vironment.
... ated step-stress and consatnt stress tests were perlotmod w electrnnic parts during the program to provide data and inforwmý*..%m which would lead to the formulation ef de~sign-life data. and screeuning Osts. The test program continued unt(I September, 1963 at which time tha parts on life testa had acOramulftt6' 6000 ~ ~ -to ; w"s az a appliwi iscresseas W_ virowimstal ioondition-L. "'he parts were thcn placed at siorv.,-conditions of 250 Celsius and zero power for ten ro aand were reactivated to tho :&me prior tei~t contiitionr for a 1 year period in June, 1964 as a ru~: mein ~J contract AF3O!602)*-341.5. The step-stress teatst which were oown'r*1ard durling the Advent Program provided da-a wbiceh wa6 analyzed during the initial period of the cotit T!'e combiettion of the rwasuits of the atep-otrtiis tests and the ----*tint at:trea tests form'%dL the basis for the determnination u.i the measurement techniques for covtrollabie accol.-ikitco testing tuchnimq'!c recommlended as a result of the contract. The parto continued on Life 'rest during the peric.4 of June 65 to Dec 65 -the utartint! date for this one year contract (A F,3CQ3O2)-3968,. The constant stress teftf sive accumulated 25, 000 to 30. 000 hours ai test ti..ie and the step-stress to~s~a were completed during the previous contracti. The tealto were ccritirwued f--it one yes~r period to provido greater confidence in the teat technique and to provide~ foi fuzshe-azaiys~s of degradLdo0n trends. ihvl definition and ertablishment of accelerated testing meth--do axid techniqueis for electiroic parts must be based inponc the actu-failure rnechantoima which exist In t-he pu-.. C~onsequently 0ýhi: provgiam, corsists of two distinct yf~t Intaf related inveotlga!I~Ig The first being the arc!Ierated, test proirain above amd the' -.ec(-.dA is the defirdition of ths physical d~gYadat1.; inechanism-rs which the parts. ethibit during the tests, "boratorv tfivestlpt!zaa were ciriducted or, ui'-t-eit and on failsed parts duiring th13 co rues of Che propitm to tdetntify thA pirt filure r'ne6, 4 nmns. In &MIuinrn, t epsrate-physics of failure fnvestiption was 'Waitutod du~rir.g this oontract co inorganic dloaew'tric capeoitors,