I used an aluminium alloy called 'Dural' for making parts for high vacuum equipment. It was very hard and could be machined to a mirror-like finish. Do you know what alloy it was?
By the way, I was always under the impression that to get a decent analysis of metals one needed to use a crystal spectrometer and prepare a flat surface for analysis as EDX could give misleading results. But I don't know much about this because most of my EDX work was on biological material which is very difficult. The specimens were always very small and usually under 700 nm thick -- extraneous X-Rays were a serious problem. Don _______________ Dr E D F Williams http://personal.inet.fi/cool/don.williams Author's Web Site and Photo Gallery Updated: March 30, 2002 ----- Original Message ----- From: "Thomas Stach" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 08, 2003 2:11 PM Subject: Re: *ist D revisited > > > Dr E D F Williams schrieb: > > > > Surely EDX would be enough? You'd need to prepare a sample of the metal to > > do a quantitative analysis? We'd only need to know the elemental > > constituents, not the exact proportions, to settle this nonsense once and > > for all. > > To determine the constituents of an alloy within a given frame of > accuracy around +/- 2% > an EDX-analysis is sufficient. > You do not necessarily need to do a metallographic preparation of the > sample - > and this is no nonsense, mister! > :-) > These are the advantages of non-destrutive methods, I do this every day. > > So I could easily tell you whether it's something in the class of > Duraluminium, St52, 42CrMo4, TiAl6V4, Inconel, CMSX-4 or whatever! ;-) > Although I doubt, they use aerospace materials... *bg* > > Perhaps you could grind off some of the coating at a spot where you > wouldn't recognise it later (inside), > if it's too thick, but you wouldn't need a cross-section. > > > Thomas > > > > > > Don > > _______________ > > Dr E D F Williams > > http://personal.inet.fi/cool/don.williams > > Author's Web Site and Photo Gallery > > Updated: March 30, 2002 > > > > ----- Original Message ----- > > From: "Thomas Stach" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Sunday, June 08, 2003 1:16 PM > > Subject: Re: *ist D revisited > > > > > > > > > > > Rob Studdert schrieb: > > > > > > > > On 7 Jun 2003 at 19:28, KT Takeshita wrote: > > > > > > > > > On 03.6.7 6:22 PM, "Pål Jensen" <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > But it is only the surface cover. The lens barrel on the 77 and 31 > > Limited are > > > > > > made of steel like most FA* lenses. > > > > > > > > > > Oh, I did not know that. I was told by Pentax that Ltd lenses are > > made of > > > > > aluminum (and glass too :-). > > > > > They have to carve a helicoid or two and I did not think steel was > > used. > > > > > > > > I personally wouldn't discount your sources, the arguments thus provided > > seem > > > > to be a lot of hearsay and definitely aren't those of materials > > scientists. > > > > > > He he, > > > here it's time for me to jump in the game. > > > Send me some samples, and I'll make you some anlysis with EDX/WDX, XRD, > > > XPS & metallography - whatever you like. > > > "Destructive" as well as "non-destructive"... > > > I could also determine the coating material and it's thickness. > > > ;-) > > > > > > > > > Thomas > > > > >
