Corrosion resistance consolidation of a diaphragm type vacuum sensor
This paper describes the corrosion resistance consolidation of a diaphragm type vacuum sensor using a high corrosion resistance material. Initially, we had fabricated a vacuum sensor using a Ru based thin film amorphous alloy, whose high corrosion resistance was confirmed in wet tests. In the high corrosion gas tests, however, the sensor resists NF<inf>3</inf> and COF<inf>2</inf> gases but does not resist ClF<inf>3</inf> gas. Therefore, we searched for new Ni based amorphous alloys which can also resist ClF<inf>3</inf> using a combinatorial search based on a MEMS process. We were able to fabricate new sensors using Ni<inf>56</inf>Nb<inf>33</inf>Ti<inf>11</inf> and Ni<inf>49</inf>Nb<inf>35</inf>Ti<inf>16</inf> amorphous alloys which were shown to resist all three mentioned gases.
Combinatorial Arc Plasma Deposition of Thin Films
In this paper, we introduce a new combinatorial thin film deposition process that uses arc plasma [combinatorial arc plasma deposition (CAPD)]. The major goal of CAPD in this study is to search for new compositions of amorphous thin film alloys. CAPD uses three cathodic arc plasma guns and the guns shoot the pulse like plasma one by one at a specific time interval. The plasma from each gun is guided onto a substrate by a magnetic field at a specific area on the substrate so as to deposit a compositionally-graded thin film. The deposited thin film is separated into 1,089 samples (the size of each is 1 ×1 mm2) by a trench grid on the substrate. The samples together are called the thin film library and all samples are numbered by the 5-bit row and column marks in the grid. To prove CAPD, a thin film library of a Pd–Cu–Si alloy system was deposited. The composition and non crystallinity of 180 samples were evaluated using energy-dispersive X-ray fluorescence spectrometer (EDX) and imaging-plate X-ray diffractometer (IP-XRD), respectively. Both measurements were performed without detaching the samples from the library. Analysis of 180 samples showed a graded composition, and some of the samples were shown to be amorphous.
Superplastic micro-forming of microstructures
Superplastic micro-forming processes have been applied to forming and fabrication of micromechanical components. Selected materials are a fine grained superplastic Al-78Zn alloy, pure iron as a transformation superplastic material, and amorphous LaAlNi, ZrAlCu alloys which exhibit a supercooled liquid state. With these materials, microformability tests have been carried out with the specially developed evaluation system by using V-grooved micro dies made of [100] silicon. The throat width of the V-groove is from 1 to 20 /spl mu/m. With these dies, micro-forging has been carried out and the characteristics of micro-formability of the material have been clarified. In a fine grained superplastic of polycrystalline aggregates, the accuracy limit of micro-formability is depend on the grain diameter. On the other hand, quite superior formability has been observed in the amorphous alloys after forming under a supercooled liquid condition. These results indicate an importance of a deformation mechanism from a view point of polycrystalline structure or a micro(/spl mu/m) scopic scale. A good micro-formability shown above has been applied to a dosed die forging of microstructures such as micro pyramids and microdouble gear system. As a result, superplastic materials and amorphous alloys are useful for micro-forming and fabrication of microstructures or components for MEMS.