APOLLO 11:
Lunar Chemistry "I'm picking up several pieces of really vesicular rock out here." That comment made by Apollo 11 astronaut Neil Armstrong as he collected lunar samples seems—at press time—to have reheated one scientific controversy. The controversy rages over whether the moon is geologically alive with active volcanoes or dead. The presence of vesicular rock— spongelike and light in weight—indicates volcanism, says NASA's Neil Nickle, a geologist and acting assistant director of the lunar sample program. The fact that such rock was found on the surface indicates it isn't too old by geologic standards— perhaps a million years, he guesses. Armstrong's observations, Nickle adds, also tie in with numerous astronomical sightings of gas clouds. "Everything points to a high probability of volcanism," he maintains. Taking a similar stand is the U.S. Geological Survey's Harold Masursky. Dr. Masursky, head of the astrogeological branch, describes the landing site as "an éjecta blanket from a young, small crater." He suggests the presence there of two possible volcanic rock types with vesicles unmodified by the impact of meteorites or considerably changed by impact of such meteorites. The views of Nickle and Masursky conflict somewhat with those of Nobel Laureate Harold Urey, one
proponent of the dead moon theory. Questioned by Victor Cohn of the Washington Post about the presence of vesicular rock that would prove that the moon is mainly volcanic in origin, rather than mildly so, Dr. Urey was quoted as saying, "I have to think about this a little bit." Although Dr. Urey was unavailable for additional comment, one of his close coworkers, Dr. Gordon J. F. MacDonald of the University of California, Santa Barbara, comments on the presence of vesicular rock. "If, indeed, the rock is vesicular, then the question is just how is it vesicular." If the rock contains smooth, rounded holes then it might be caused by solidification of magma around gas bubbles, implying volcanic origin. But he believes that considerable chemical analyses will have to be performed at the Lunar Receiving Laboratory and afterwards by the principal investigators before the true nature of the rock's origin can be determined. "What surprises me," he says, "is that there were so few surprises in what the astronauts found when they landed." Indeed, some of Armstrong's observations radioed back to the Manned Spacecraft Center did tend to confirm previous findings. At one point he said that "these boulders look like basalt," adding that "they contain about 2% white crystals." Buzz Aldrin also spotted rocks which he identified as biotite, a form of mica consisting of a silicate of iron, magnesium, potassium, and aluminum.
Scratching the surface Astronauts Aldrin and Armstrong take samples of lunar soil
CLADDING:
Metal to Any Other "It doesn't matter if the product is metal or plastic—precast or in rolled sheet form—a metal clad can be applied to its surface in thicknesses ranging from 2 to 250 mils." So says Dr. Ernest J. Breton, vice president of Composite Sciences, Inc., in disclosing last week that the company has come up with a new process for converting metal powders into a rubberlike form for use in cladding. The Newport, Del., firm says it expects the process to enable it to penetrate markets, such as chemical, automotive, and heavy equipment, where surface cladding is now being carried out by plasma or flame spraying techniques. Aimed especially at precast forms, the process has immediate potential for cladding mixer blades to prevent corrosion, and cladding teeth and various cutting blades, valve seats, dies, and bearings to improve wear resistance. Film production, at this time, is on a pilot scale. Composite Sciences doesn't plan to make the film commercially available anytime soon, but will offer cladding services. Basically, the process involves mixing a metal base alloy with a polymeric binder. An example would be a nickel-base alloy containing 82.1% nickel, along with 7% chromium, 5% silicon, 2.9% boron, and 3% iron. Following a proprietary step, the cladding is rolled out as a rubberlike film. Varying the alloy constituent mix determines physical properties (corrosion or wear resistance). Shapes can be cut from the film and placed on surfaces to be clad. On a metal surface, for example, a pure metal clad is made by heating the object in a tube or other commercial furnace at 1850° to 2000° F. It takes 15 to 30 minutes to fire off the binder and effect the bond, depending on substrate thickness. A plastic surface (or metal, if desired) can be clad by converting the film to a free-standing form by sintering. It is then applied by fusing, sintering, or adhesive bonding. Limitations of the process, Dr. Breton points out, are based on properties of the alloys and, to some extent, those of the substrate. Melting points of clad and substrate must be compatible, for example. But Composite Sciences claims that clads can be made of any metal in any volume percentage up to 95%? and attached to any material. Cost for cladding a surface will be about 1 cent per mil per square inch. By comparison, flame spraying costs about i y 2 cents per mil per square inch, Dr. Breton notes. JULY 28, 1969 C&EN
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