PurposeThe purpose of this paper is to characterize electrical parameters of amorphous Ni‐P resistive layers used for fabrication of precise resistors.Design/methodology/approachNi‐P resistive layers were produced by the chemical process in water solution using Ni2 +  and H2PO2− ions. The paper presents the results of the studies concerning the influence of bath acidity and conditions of thermal stabilization on the structure and temperature coefficient of resistance of Ni‐P alloy.FindingsThe temperature coefficient of resistance of amorphous Ni‐P layers was found to depend significantly on the parameters of chemical metallisation process. It was stated that the changes of through‐casing resistivity versus the acidity of technological solution have roughly parabolic characteristics.Originality/valueIn this paper, it was at first explained how the changes of the structure of Ni‐P resistive layers depend on their temperature coefficient of capacitance.

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Purpose – This paper aims to select parameters such as temperature thermal stability and temperature coefficient of resistance (TCR) for Ni–P resistive alloys obtained by electroless metallization. Ni–P alloys are used in the manufacture of precision resistors characterized by TCR in the range of ± 10 ppm/K. The correlation of the technological parameters with the electrical properties of resistors enables the accurate prediction of the TCR resistors. Design/methodology/approach – The Ni–P layers were obtained by a continuous process at about 373 K in a solution with the acidity of pH = 2 and then dried for two hours at 393 K. Subsequently, the Ni–P layer was stabilized for two hours in the temperature range of 453-533 K. Resistance was measured with an accuracy of 1 mΩ. TCR was determined with an accuracy of 1 ppm/K in the temperature range 298-398 K. In the next stage of the investigation, the increase in TCR of the Ni–P alloy was correlated with the increase in stabilization temperature. Scanning electron microscope images of the alloy surface were studied to assess grain sizes and to relate the average grain size with TCR values of resistive alloys. The X-ray diffraction analysis was performed to determine the crystallization temperature of Ni–P alloy. Findings – The conducted investigation showed that the TCR increase in alloy is a linear function of stabilization temperature in the temperature range in which transition from amorphous phase to crystalline phases did not occur. TCR increase in Ni–P alloy arises from the increase of average size of grains resulting in decrease of scattering of electrons on grain boundaries. The analysis of alloy composition in chosen fragments of surface shows inhomogeneity growing with decreasing analyzed surface dimensions which proves that, before the stabilization, the structural arrangement of alloy is inconsiderable. Originality/value – The obtained results are the first attempt to relate the morphology of surface with TCR of alloy and demonstration of linear dependence between an increase in TCR of amorphic Ni–P alloy and stabilization temperature of resistive layer. Such correlations are not described in available literature.

Purpose The paper aims to present a research on the impact of the stabilization process of a thin metallic layer (Ni-P) produced on a ceramic surface (Al2O3) by means of electroless metallization on its electric parameters and structure. On the basis of the research conducted, the existence of a relationship between resistance (R) and the temperature coefficient of resistance (TCR) of the test structure with a Ni-P alloy-based layer and the temperature of stabilization was proposed. Design/methodology/approach Metallic Ni-P layers were deposited on sensitized and activated substrates. Metallization was conducted in an aqueous solution containing two primary ingredients: sodium hypophosphite and nickel chloride. The concentration of both ingredients was (50-70) g/dm3. The process lasted 60 min, and the metallization bath pH was kept at 2.1-2.2, whereas the temperature was maintained at 363 K. The thermal stabilization process was conducted in different temperatures between 453 and 623 K. After the technological processes, the resistance and TCR of the test structures were measured with a micro ohmmeter. The composition and the morphology of the resistive layer of the structures examined was also determined. Findings The dependence of the resistance on the temperature of the stabilization process for the temperature range 553 to 623 K was described using mathematical relationships. The TCR of test resistors at the same thermal stabilization temperature range was also described using a mathematical equation. The measurements show that the resistive layer contains 82.01 at.% of nickel (Ni) and 17.99 at.% of phosphorus (P). Originality/value The results associate a surface morphology Ni-P alloy with the resistance and TCR according to temperature stabilization. The paper presents mathematical relationships that have not been described in the literature available.

The paper describes a new method of obtaining of Ni-W-P resistor layers, featuring elevated electrical stability. Such layers may be introduced into the manufacturing process of precise metal film resistor. Streszczenie. Artykuł opisuje nową metodę uzyskiwania warstw rezystywnych Ni-W-P, charakteryzujących się podwyższoną stabilnością elektryczną. Warstwy te mogą być wykorzystane do procesu wytwarzania precyzyjnych rezystorów warstwowych. (Rezystywne warstwy Ni-W-P wytwarzane metodą chemicznej metalizacji).