Jaromir Drapala

Vysoká škola báňská - Technical University of Ostrava · Non-ferrous, refining and recycling

The aim of this study was to characterize a Zn-Mg type soldering alloy and direct soldering of SiC ceramics with a copper substrate. The Zn1.5Mg solder exerts a wider melting interval. The temperature of the eutectic reaction was 365 °C, and the liquidus temperature was 405 °C. The microstructure of the soldering alloy is comprised of a zinc matrix...

The aim of this study was to characterize a Sn-Ti solder alloy containing 6 wt.% SiC nanoparticles and evaluate its use for direct soldering of SiC ceramics to a copper (Cu) substrate. Soldering was performed with direct ultrasound activation. The average tensile strength of the solder alloy was 17.1 MPa. Differential Thermal Analysis (DTA) analysi...

The manuscript explores the feasibility of recovering zinc and iron from waste galvanic sludge generated during galvanic plating processes. Galvanic sludge, characterized by elevated concentrations of heavy metals, represents a suitable candidate for hydrometallurgical recycling. The primary objective of the experimental and practical phases was to...

The aim of the research was to characterize the soldering alloy type Zn-Mg-Sr and direct the soldering of SiC ceramics with Cu-SiC-based composite. It was investigated whether the proposed composition of the soldering alloy was appropriate for soldering those materials at the defined conditions. For the determination of the solder melting point, TG...

This research aimed to study a Bi–Ag–Mg soldering alloy and the direct soldering of Al2O3 ceramics and Ni–SiC composites. Bi11Ag1Mg solder has a broad melting interval, which mainly depends on the silver and magnesium content. The solder starts to melt at a temperature of 264 °C. Full fusion terminates at a temperature of 380 °C. The microstructure...

The aim of this research was to study the interaction and solderability of Al2O3 ceramics and Ni-SiC composite by use of an active solder type Bi11Ag1.5Ti1Mg. The chemical composition of the solder is 86.5 wt% Bi, 11 wt% Ag, 1.5 wt% Ti, 1 wt% Mg. Soldering was performed by ultrasonic activation. This solder has a wide melting interval with the init...

The paper deals with the possibility of obtaining zinc and iron from waste galvanic sludge, which arises during galvanic plating. Galvanic sludges, which contain more significant amounts of heavy metals, form wastes that are suitable for recycling. These arise during the treatment of wastewater from the operation of the electroplating plant. It is...

This paper deals with the possibility of obtaining zinc from waste galvanic sludge, which is formed during galvanic plating. The aim of the experimental and practical part was to obtain zinc after the leaching of galvanic sludge. Leaching was performed in sulfuric acid, nitric acid and hydrochloric acid at different temperatures and time intervals...

The aim of this research was to study the wettability and solderability of SiC ceramics by the use of an active solder of the type Sn5Sb3Ti in a vacuum by electron beam heating. This solder exerts a narrow melting interval, and only one thermal effect, a peritectic reaction, was observed. The liquidus temperature of the solder is approximately 243...

The aim of this research was to characterize soldering alloys of the type Sn–Sb–Ti and to study the ultrasonic soldering of SiC ceramics with a metal–ceramic composite of the type Cu–SiC. The Sn5Sb3Ti solder exerts a thermal transformation of a peritectic character with an approximate melting point of 234 °C and a narrow melting interval. The solde...

Effects of Cerium (Ce) addition on solidification structure of a low-carbon 42CrMo4 steel was investigated. The addition of up to 0.067 wt.% of Ce in the steel produced greatly improved solidification structure with a suppressed columnar grain zone, finer grain size in an equiaxed grain zone and zero area fraction of casting shrinkage cavity. The a...

The aim of the research work was to characterize the soldering alloy type Bi-Ag-Ti and to study the direct soldering of silicon and copper. Bi11Ag1.5Ti solder has a broad melting interval. Its scope depends mainly on the content of silver and titanium. The solder begins to melt at the temperature of 262.5 ∘C and full melting is completed at 405 ∘C....

The aim of the research was to characterize the soldering alloy type Zn–Al–Cu and study the fluxless ultrasonic soldering of the combination of aluminum alloy type Al7075 with copper substrate. The Zn–Al–Cu solder is of the close-to-eutectic type with two phase transformations: the eutectic transformation at 378 °C and the eutectoid transformation...

The aim of this research is to characterize the soldering alloy Zn6Al6Ag, and to study the ultrasonic soldering of an Al2O3/metal–ceramic composite (Al/Al2O3). Zn6Al6Ag solder presents a quasi-eutectic structure with a melting point around 425 °C. The solder microstructure consists of a (Zn) + (Al) matrix, reinforced with a silver AgZn3 phase. A bo...

This research aims to develop the direct soldering of aluminum nitride (AlN) ceramics with a copper substrate using Zn–Al–Mg solder. The solder type, Zn5Al3Mg, has a close-to eutectic composition with a melting point of 359 °C. The microstructure of Zn–Al–Mg solder is composed of solid solution (Al), solid solution (Zn), an Mg2Zn11 phase and a mino...

In this work, the Ti6Al4V specimens produced by selective laser melting were mechanically tested in non-heat treated condition and fracture surface features were compared with this one of the material prepared using conventional casting and forging. The results of the fractography observation for both types of the samples were explained on the base...

The study of the effect of thermal treatment conditions on NiTi alloy used in biomedicine was carried out. The experimental samples of NiTi alloy with 55.8 wt% Ni were subjected to the heat treatment. The thermal regimes consisted of aging treatment at 300, 350 and 400 °C for 30 minutes followed by air cooling. The microstructures before and after...

Purpose This study aims to solder AlN ceramics with a Cu substrate using an active type Sn-Ag-Ti solder. Soldering was performed with power ultrasound. The Sn3.5Ag2Ti alloy was first studied. Design/methodology/approach It was found to contain a Sn matrix, where both Ag phase – ɛ-Ag3Sn – and Ti phases ɛ-Ti6Sn5 and Ti2Sn3 – were identified. Ti co...

The study aimed at direct flux-free soldering of metal-ceramics composite (MMC) with a copper substrate. Soldering was performed with type Zn10In1Mg Zn-solder. The soldered joints were fabricated using power ultrasound. The solder used consists of a zinc matrix, while the solid solution (In) and MgZn 2 phase were segregated on the grain boundaries....

New types of lead-free solders on the base of tin with addition of metals Ag, Al, Bi, Cu, In, Mg, Sb, Zn were studied. Various alloys were experimentally prepared by smelting of metals in an inert atmosphere or in vacuum in resistance furnace. Purity of metals was minimally 4N. The specimens of solders were studied metallographically including the...

The aim of the research was to characterize the soldering alloy In–Ag–Ti type, and to study the direct soldering of SiC ceramics and copper. The In10Ag4Ti solder has a broad melting interval, which mainly depends on its silver content. The liquid point of the solder is 256.5 °C. The solder microstructure is composed of a matrix with solid solution...

The positive effect of the hydrogen on hot deformation behaviour at 700 and 750 °C was investigated after thermal hydrogen treatment of Ti6Al4V and Ti26Nb alloys. Comparing the results obtained for the non-hydrogenated and hydrogenated specimens of both alloys, it was found that the hydrogen content as high as 1325 wt. ppm has an obvious benefit ef...

The Sn–Zn–Al alloys are one of significant candidates in the proposal of alternative lead-free solders for higher temperature soldering. This paper deals with the study of the aluminum–tin–zinc system. Twenty Sn–Zn–Al alloys together with six binary Sn–Zn alloys were prepared and studied experimentally. Alloys were prepared from pure Sn, Zn and Al...

Superelastic behavior of off-stoichiometric NiTi alloys is significantly affected by microstructure changes due to heat treatment. Applying appropriate thermal treatments important effects on microstructural changes, transformation temperatures and thermomechanical properties of final NiTi products can be achieved. The experimental samples of NiTi...

Charakteristika slitin Ni-Al-Mo připravených metodou plazmové metalurgie a elektronového zonálního tavení doc. Ing. Jitka Malcharcziková, Ph.D.; Ing. Martin Pohludka, Ph.D.; prof. Ing. Miroslav Kursa, CSc.; Ing. Daniel Petlák; Ing. Michal Madaj; Ing. Petr Kawulok, Ph.D.; Ing. Rostislav Kawulok, Ph.D.; prof. Ing. Jaromír Drápala, CSc.; doc. Ing. Ivo...

The influence of rare earth metals (REM) addition on solidification structure of the low-carbon 42CrMo4 steel was investigated. Alloys were prepared by means of a centrifugal casting. The addition of cerium, praseodymium or mischmetal in the steel produced greatly improved solidification structure with a suppressed columnar grain zone, finer grain...

The paper deals with a possibility of zinc and cobalt extraction from refuse after sphalerite mineral leaching. It contains theoretic analysis of hydrometallurgical processes. Practical part describes samples and their leaching in 10% and 20% sulphuric acid. In the end of the paper it is evaluated under which conditions the highest yield of zinc an...

A general trend in steelmaking industry is to increase strength, resistance to brittle fracture and fatigue properties of steel products at favorable price. Achieving fine-grained microstructure during austenite to ferrite transformation is a basic prerequisite to improve the mechanical properties. The desired transformation can be achieved in seve...

The results of an experimental study on influence of cerium addition on structural characteristics of 42CrMo4 steel are presented. Alloying with cerium was carried out using profile filled with powdered mixture of mischmetal. The samples were taken from two ingots cast in the VHM's steelworks with standard time of casting of about 14 minutes. Three...

Thirteen ternary Al-Sn-Zn alloys with various contents of elements were prepared experimentally. The alloys were studied metallographically after casting and after long-time annealing in vacuum. X-ray structural and chemical micro-analyses (EDX, WDX) of the phases were measured. Temperatures and latent heats of characteristic phase transitions (liq...

Theoretical and experimental study on influence of addition of selected non-ferrous metals and mischmetal on microstructural characteristics in special Cr–Mo steels were performed. A number of binary iron-admixture systems were theoretically studied and equilibrium distribution coefficients were recently computed. Cast samples of Cr–Mo steel with C...

This paper is dedicated to the development and optimization of the porous titanium materials suitable for biomedical usage in traumatology. Main aim of the presented research activities is focused on preparation of biocompatible titanium based materials with controlled porosity. It was found that titanium specimens with total porosity approximately...

Using an ultrasonic method, the measurement of longitudinal and transversal velocities v of ultrasonic waves in the major crystallographic directions of pure-tungsten single crystals and tungsten single crystals alloyed with Ta and Mo was performed. Single crystals with a [110] crystallographic orientation were prepared by plasma-arc melting. Cryst...

This paper deals with FEM analysis of six models that represents human cortical bone, cast TiAl6V4 alloy and porous TiAl6V4 with different pore diameters. Reliable data for the simulations were achieved by meta-analysis that consisted from 53 scientific works. Strain value was chosen with a respect to the frequent daily activities such as walking....

The study of microstructure and fracture surfaces was performed on specimens of reconstruction plate, reconstruction nail and elastic nail. The composition and phase analysis of microstructure was performed by scanning electron microscope (SEM) JEOL JSM - 6490LV equipped with EDS INCA X - ACT probe. Examination of fracture surfaces by SEM confirmed...

The distribution of tantalum in molybdenum and tungsten single crystals during electron beam fl oating zone melting under different crystallization conditions was investigated. The performed line chemical analysis of specimens proved creation of tantalum micro segregation, so-called growth striations, which showed themselves on concentration proĀ l...

The manufacturing program of the company VÍTKOVICE HEAVY MACHINERY a.s. comprises production of a wide range of structural steels for the high exposed machine parts, such as shafts of wind power stations, turbine shafts, gears, etc. Due to the ever increasing demands of customers to increase the service properties of steel while maintaining the rea...

Problems of reactive diffusion at the interface solid phase - melt were studied theoretically and experimentally. A theoretical description of the kinetics of dissolution of the solid phase in the melt is presented for the case of planar dissolution. The main intention was to study experimentally the copper dissolution in melts of various solder al...

The article informs about creation and activities of the Regional Materials Science and Technology Centre (RMSTC) at the VSB-Technical University of Ostrava, Faculty of Metallurgy and Materials Science. The first stage of the project (“Start-up” stage) is focused on building of the centre in terms of investments into equipment, infrastructure and c...

High purity and perfection of the structure made metallic single crystals indispensable objects of basic research. Single crystals of refractory metals became, thanks to their unique complex of physical mechanical and chemical properties, real materials of modern engineering. Their plasticity, low gas evolution, increased resistance during thermal...

The aim of the work was to study the creation of micro- and macro-segregation of iridium in low-alloyed molybdenum single crystals after electron beam zone melting (floating zone technique) depending on various conditions of crystallization. In order to evaluate relations between the chemical inhomogeneity and structural defects and their influence...

Using the finite element method (FEM) deformation behaviour in material after severe plastic deformation was simulated. As for the extruded material the Ti-6Al-4V alloy was chosen. Deformation was introduced into the material in the following ways: The ECAP method and ECAP with partial back pressure, ECAP-PBP method. Among the main parameters obser...

Theoretical and experimental investigations of the crystallization processes of alloys of stoichiometric compositions with peritectic transformations have been carried out. It is shown that the crystallization process in a wide cooling rate range follows the non-equilibrium way with the formation of the non-equilibrium phases. A method to obtain sa...

The Sn–Zn–Al system was studied in connection with the possible substitution of lead-based solders for temperatures up to 350 °C. Ternary alloys with up to 3 wt% of aluminium were prepared. The investigated alloys lie close to the monovariant line (eutectic valley) of the Sn–Zn–Al system. The temperatures of phase transitions of six binary Sn–Zn re...

Parameters of sub-structure of single crystals of low-alloyed tungsten alloys from the system W-Nb and W-Mo were investigated after thermal cycling in argon protective atmosphere. The mode of thermal cycling of tungsten based single crystals consisted of heating to the temperature of 2500 °C and of cooling to the temperature of 500 °C with dwell of...

Problems of reactive diffusion at the solid phase and melt contact are studied theoretically. The rate constant is a fundamental parameter characterizing the dissolving rate at a certain configuration of experiment. Relationships between the solid phase dissolving rate, i.e. the solid phase interface boundary movement in the melt, and rates of grow...

Two production methods of sintered Nd-Fe-B magnets were compared, and the effect of heat treatment (НТ) regimes on magnetic properties of these magnets was studied. Sintered (Nd,Dy)-Fe-В magnets with ~3 wt.% Dy were prepared using method of single alloy and method of "mixtures" which means the mixing of powders of a basic alloy whose composition is...

The aim of this work is an experimental study of lead-free solders. Ternary and binary alloys with different ratios of individual elements Ag, Al, Bi, Cu, In, Mg, Sb, Sn and Zn were prepared experimentally. The study of low-fusing solder alloys was performed with the aspect of observing their selected physical, chemical, structural and technologica...

X-ray diffraction, differential thermal analysis, and electron microscopy are used to study the crystal structures and formation sequence of intermetallics in the Lu-Pd system in a composition range of Pd-(0–50 at %) Lu. The alloys are synthesized using high-purity lutetium. Within the composition range under study, the system is characterized by t...

Al-Sn-Zn alloys are considered to be a good alternative for lead-containing solders; however, their physical properties at high temperatures are investigated insufficiently. In this work we have studied density (by gamma-absorption method), electrical resistivity (by contactless method in rotating magnetic field) and magnetic susceptibility (by Far...

The study of influence of Fe and Ti alloying elements in the Ni3Al intermetallic alloy on diffusion feature in Ni/Ni3Al-Me (Me = Fe or Ti) joints was performed using the diffusion couple technique. Four sets of diffusion couples of diverse compositions prepared by means of resistance welding or electron beam welding in vacuum were used. The concent...

Problems of reactive diffusion at the solid phase and melt contact were studied theoretically and experimentally. The main intention was to calculate the time course of the solid phase dissolving in the case of cylindrical dissolving. These calculations were carried out on the assumption for the rate constant of dissolving K = const. In our work we...

Problems of reactive diffusion at a solid phase - melt contact were studied theoretically. The main intention was to calculate the time course of the solid phase dissolving in the case of planar dissolving. In our work we give heed especially to the dominating process, which is the solid metal A dissolving in solder melt B. During the dissolving, m...

In this work we give heed especially to the dominating process which is the solid metal A dissolving in the melt B. During the dissolving, the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase...

The solution of the diffusion equation at the non-stationary boundary represents the so-called Stefan problem which can be solved by means of the thermal potential of a double-layer with the accuracy sufficient for description of diffusion phenomena. The results were methods for determination of the mean values of the interdiffusion coefficients. T...

Some results of the study of Al-Sn-Zn alloys, which can be a possible lead-free solder candidates for high temperature-applications, are presented in this paper. Thirteen ternary Al-Sn-Zn alloys with high chemical and structural homogeneity were prepared in a resistance furnace in evacuated ampoules. The alloys were studied metallographically. Thei...

The aim of the work was to determine the emission pattern of tungsten single crystal with crystallographic orientation of the growth axis <310> prepared by the electron beam zone melting applying the "floating zone" method at the Department of Non-ferrous metals, refining and recycling VŠB-Technical University Ostrava as a new type of prospective m...

When developing new types of materials with special properties for the automotive industry, steels with high content of manganese (up to 25 wt. % Mn) were studied. These steels embody increased failure resistance, high level of deformation hardening, plastic response and high value of energy absorption in crash situations [1,2]. The aim of our work...