Negative electrodes for nickel-cadmium accumulators: their properties as determined by impregnation procedure

Sintered negative electrodes for nickel-cadmium secondary cells were studied. Model electrodes prepared by means of three different impregnation methods were evaluated. It was demonstrated that the impregnation procedure may affect properties of active mass and the service life of electrodes in a significant way.     

Sealed NiCd cells: The temperature behaviour of electrodes in excess of electrolyte

The temperature behaviour of both cadmium and nickel oxide electrodes of the sintered type (as used in sealed NiCd cells) has been investigated     

Use of GDOES method for evaluation of the quality and thickness of hot dip galvanised coating

The paper describes an assessment of thickness and quality of hot-dip galvanised coating by means of the glow discharge optical emission spectrometry method (GDOES). For comparison, a metallographic analysis was made using an optical microscope. An important factor influencing thickness and quality of the hot-dip galvanised coating is chemical composition of steel, particularly the amounts of silicon. Structural steels with a low amount of silicon S235JR and S355J2 were chosen for the experiment and high-strength steel S690QL with a high amount of silicon was chosen for comparative purposes. The results of the coating thickness measurement by means of GDOES and optical microscopy show only minimal differences. Steel S690QL shows a thick and uneven zinc coating. In the case of steels S235JR and S355J2 an optimal hot-dip galvanised coating was observed.     

Textural changes in coal after reduction with lithium in ethylenediamine

Textural changes in six bituminous coals (from 16.3 to 31.4% VM daf), after reduction with lithium in ethylenediamine at 373 K, have been established according to N₂ isotherms at 78 K and C0₂ isotherms at 298 K. Changes in pore volume were determined from the real and apparent densities and from the volume filling of micropores. Macroscopic changes on the grain surfaces were determined by means of the scanning electron microscope. It appears from these experiments that an initial increase in total porosity is caused by the action of ethylenediamine alone, while the final changes, primarily in the meso- and macropores (similar to disturbances of the external grain surface), result from the reduction process. The location of the added ethylenediamine in the bulk of the reduced coal has also been considered.     

Mechanical Properties of Steel P92 Welded Joints Obtained By TIG Technology

Metal Science and Heat Treatment - Mechanical properties of P92 steel welded joints obtained using the TIG (141) technology have been studied upon post-welding heat treatment (PWHT). The...     

Protection of sealed nickel-cadmium cells against cell voltage reversal II. Influence of the separator on the formation of cadmium bridges

After studying three types of polyamide fabric, each with different physical parameters and different properties, as separators in an alkaline electrolyte, two widely differing materials were selected. These were evaluated by scanning electron microscopy both before and after the chemical deposition of cadmium hydroxide (Cd(OH)₂). Their physical parameters were correlated with their efficiency in the formation of protective cadmium bridges in sealed nickel-cadmium accumulators during deep discharge accompanied by voltage reversal. Two types of sealed accumulators were employed with differing electrode geometry and interelectrode distance, which was shown to be related to the Cd(OH)₂ content of the separator.