I received the broken shards of the alumina tube from the MFMP Parkhomov-like experiment from Ryan Hunt. The intent was to have analyzed the metal film on the inside of the alumina to see if it is Li-Al alloy and to try to re-assemble the pieces to form at least one full circumference of the tube. So far, piecing the tube together has been unsuccessful; however, I have found 2 pieces each having a large portion of the circumference - in one case 94 degrees of an arc and in another 106 degrees. In both cases, the ID of the alumina tube is completely covered with the metal film with no visual evidence at the boundaries of the metal tapering in thickness. Statistically, there is nothing to suggest that these pieces were centered on the bottom of the tube. Also, none of the shards show any transition from covered to uncovered with metal.
Based on this, I surmise that the interior of the tube at 1057C had a complete circumferential ring of liquid Li-Al in a thin continuous layer. It appears that the liquid Li-Al wetted to the alumina, perhaps with the hydrogen and high temperature cleaning of the alumina surface. With the wetting, the surface tension of the liquid metal, and the high interior pressure, I believe the liquid metal was forced to cover the inner circumference of the tube while it was liquid. The chemical effect of the Li on the alumina may also have been instrumental in the wetting of the metal solution to the ceramic. There is no supporting evidence for a gravity fed river of liquid Li-Al metal at the bottom of the tube. Visual examination under the microscope shows the supposed Li-Al film to be developing small white crystals, well distributed upon its surface. These are probably LiOH from exposure to the humidity in the air. Alan Goldwater is being sent sample shards with the metal coating to do a microscope video of an etch in water. The Vale T255 Ni, that was 90% by weight of the fuel, sintered into a porous rod the shape of the interior of the tube. After the explosion, the sintered rod of Ni was found intact in the remains of the SiC heater. There is no evidence that this Ni was ever bonded or immersed in the Li-Al metal. Though contact was likely, it appears that the molten Li-Al did not wet to the Ni. The samples will also be examined in the SEM and with XRF. Bob Higgins On Thu, Feb 12, 2015 at 5:59 PM, Bob Higgins <[email protected]> wrote: > I am going to re-assemble the pieces of the reactor tube to determine more > about the metal film deposited on the inside of the tube. In one shard, it > looks to be about 0.0037" in thickness and appears as a cooled, once liquid > metal. It is probably a Li-Al alloy. The liquid Li-Al alloy may form a > gravity fed river on the bottom of the reactor tube. Reconstruction of the > tube will tell us whether this was a gravity fed river or if it was > deposited around the complete circumference. Also, we will be having, at > minimum, XRF done on both the metal on the alumina, and the sintered Ni rod > that was left after the experiment (in combination with SEM views). > > Another observation is that there is NO evidence of alumina chemical > erosion by the Li. There is no evidence yet that this was not a chemical > weakening of the tube - it appears to be a simple hot, high pressure > failure of the tube. This tube was notably thinner than Parkhomov's tube. > > Bob Higgins >
