Michimasa Uchidate

Development of a roughness measurement standard with irregular surface topography for improving 3D surface texture measurement

In this study, measurement standards with irregular surface topography which can be used for surface texture measuring instruments of various measurement principles are proposed, and the verification system for surface texture measuring instruments is established using the measurement standard. We have generated the software gauge data with 3D irregular surface texture using the non-causal 2D auto-regressive model (2D AR model). This model can generate periodic irregular surface topography data from specified surface texture parameters, and based on the generated software gauge data, the measurement standards were manufactured by machining with a diamond ball end mill. The short wavelength components which cannot be processed by the ball end mill were removed from the original machining data by the morphological filter. Manufactured measurement standards were measured using three types of surface texture measuring instruments. Proposed measurement standards can be used for various types of measuring instruments.

A Study on Surface Material Measures for Areal Surface Texture Measuring Instruments: Measuring Conditions for the Areal Profiling

This paper describes the software gauge data for surface texture standard using the non-causal 2D auto-regressive model (A-R model). This model can provide with 3D irregular surface topography and intentional geometrical characteristics from specified surface texture parameters. The measurement area consists of a periodical combination of the generated sampling area data. The surface roughness parameters introduced from the gauge data on a defined evaluation area can be insensitive to size and location of the evaluation area size. Adequate measuring conditions to utilize the surface material measures were investigated and then the evaluation area and sampling distance for areal profiling by a stylus instrument were clarified.

Multilayered Sn/Ag 3 Sn electroplating on Cu alloys for high reliable electronic/electric materials

We report a multilayered Sn/Ag film electroplated on Cu alloys with high reliability as promising coating materials for LED lead-frames and for electric connectors. The multilayered Sn/Ag films consisted of an Ag-Sn alloy film with 30-80 nm-thick as Ag3Sn phase covered on a 1 μm-thick Sn film on Cu alloy substrates. The as-deposited Sn/Ag3Sn films exhibited a high specular reflectivity around 70% at the wavelengths of 480 nm, which was lower than a commercial bright Ag film with total reflectivity of 90% but much higher than a commercial bright Au film in 24% at the same wavelength. It was found through an accelerated sulfuring test that, the reflectivity of the Sn/Ag3Sn films was almost unchanged even after immersing in a 0.2% (NH4)2Sx solution for 60 min, compared to the abrupt decrease to 15% for the conventional Ag film even after immersing for 10 min. The excellent sulfuring resistance and durability of the multilayered Sn/Ag3Sn films can be attributed to the existence of a stable SnO2 film existed on the surface of Ag3Sn alloy, which was revealed by a UPS analysis in a vacuum chamber by heating at 473 - 673 K, thus protecting underneath Ag3Sn alloy film and inhibiting the chemical reaction of Ag and S2- ions.

Relationship between vacuum degree and measurement accuracy of thermal conductivity using quasi-steady state measurement

This paper describes an improvement of a measurement method of short measurement time for thermal conductivity of a novel thermal interface material (TIM). High electric insulation performance and high thermal conductivity is strongly needed for the novel TIM in order to use for insulation between inverters and water cooling jacket of Electric Vehicles (EVs) and Hybrid Electric Vehicles (HEVs). The improvement of novel TIM needs long time because the measurement of thermal conductivity. Therefore, a new measurement method that can measure the thermal conductivity in short time with high accuracy is strongly needed. We have been focusing on an improvement of measurement method of thermal conductivity in order to achieve the reduction of the measurement time. As a result, we suggested Steady Temperature Prediction Method (STPM) that predicts steady temperature from transient temperature history in equipment. In this paper, we tried obtaining the relationship between vacuum degree and optimum time period (minimum time period) that is necessary to predict the steady temperature.

Basic Study on reduction of measurement time for evaluating thermophysical properties of insulation heat dissipation sheet based on quasi-steady state measurement

This paper describes an improved measurement method for fast evaluation of thermophysical properties of an insulation sheet. The sheet is used to insulate inverter and water cooling jacket in an electric or hybrid electric vehicles. A large number of iterations of steady state measurement is required to perform parameter study for various composition of the sheet. However, steady state measurement generally needs very long time even only once. From the above reasons, it is necessary to reduce measurement time while keeping accuracy. Here, quasisteady state method is one of the methods of reducing measurement time by performing a prediction while keeping accuracy. Transient temperature response and steady temperature can be obtained by prediction faster than steady state method. Accuracy of prediction and measurement time will be changed by controlling application range. In this report, the availability of quasi-steady state method was investigated by comparing prediction results with steady state results of 3D thermal analysis and experiment. Especially, thermal conductivity was evaluated as a criterion. Then, the predicted thermal conductivity was derived from the predicted steady temperature. Through the investigation, in terms of accuracy, the quasi-steady state method was available when surrounding condition was perfectly insulated. On the other hand, in terms of the reduction of measurement time, a thinner thickness of metal block required a shorter measurement time because of the decrease in the heat capacity.

Effects of Water Environment on Tribological Properties of DLC Rubbed Against Brass

The effects of water environment such as temperature and dissolved ions on tribological properties of DLC against brass were studied for development of the water-lubricated hydraulics, valves and cylinders based on metal. A ball-on-disk type rotating tribotester was used for detailed examination of above mentioned factors. DLC was deposited on the disk by the unbalanced magnetron spattering system. Pure water and quasi-tap water were used to study the effects of dissolved ions. The results show that temperature and dissolved ions have major impact on the wear of DLC. EPMA, XPS and AES indicate that tribo-layer on the metal surfaces, consists of carbon and the base metal and some element from water, plays important role for the phenomena.Copyright