The demand for orthopedic implants is increasing, driven by a rising number of young patients seeking an active lifestyle post-surgery. This has led to changes in manufacturing requirements. Joint arthroplasty operations are on the rise globally, and recovery times are being reduced by customized endoprostheses that promote better integration. Implants are primarily made from metals and ceramics such as titanium, hydroxyapatite, zirconium, and tantalum. Manufacturing processes, including additive manufacturing and thermal plasma spraying, continue to evolve. These advancements enable the production of tailored porous implants with uniform surface coatings. Coatings made of biocompatible materials are crucial to prevent degradation and enhance biocompatibility, and their composition, porosity, and roughness are actively explored through biocompatibility testing. This review article focuses on the additive manufacturing of orthopedic implants and thermal plasma spraying of biocompatible coatings, discussing their challenges and benefits based on the authors’ experience with selective laser melting and microplasma spraying of metal-ceramic coatings.

This study investigates the in vitro biocompatibility, corrosion resistance, and adhesion strength of a gas abrasive-treated Ti6Al4V alloy, alongside microplasma-sprayed titanium and tantalum coatings. Employing a novel approach in selecting microplasma spray parameters, this study successfully engineers coatings with tailored porosity, roughness, and over 20% porosity with pore sizes up to 200 μm, aiming to enhance bone in-growth and implant integration. This study introduces an innovative methodology for quantifying surface roughness using laser electron microscopy and scanning electron microscopy, facilitating detailed morphological analysis of both the substrate and coatings. Extensive evaluations, including tests for in vitro biocompatibility, corrosion resistance, and adhesive strength, revealed that all three materials are biocompatible, with tantalum coatings exhibiting superior cell proliferation and osteogenic differentiation, as well as the highest corrosion resistance. Titanium coatings followed closely, demonstrating favorable osteogenic properties and enhanced roughness, which is crucial for cell behavior and attachment. These coatings also displayed superior tensile adhesive strengths (27.6 ± 0.9 MPa for Ti and 28.0 ± 4.9 MPa for Ta), surpassing the ISO 13179-1 standard and indicating a robust bond with the substrate. Our findings offer significant advancements in biomaterials for medical implants, introducing microplasma spraying as a versatile tool for customizing implant coatings, particularly emphasizing the superior performance of tantalum coatings in terms of biocompatibility, osteogenic potential, and corrosion resistance. This suggests that tantalum coatings are a promising alternative for enhancing the performance of metal implants, especially in applications demanding high biocompatibility and corrosion resistance.

Hydroxyapatite (HA) has become a widely used material for bone grafting and surface modification of titanium-based orthopedic implants due to its excellent biocompatibility. Among various coating techniques, microplasma spraying (MPS) has gained significant industrial relevance. However, the clinical success of HA coatings also depends on their adhesion to the implant substrate. Achieving durable fixation and reliable biological integration of orthopedic implants remains a major challenge due to insufficient coating adhesion and limited osseointegration. This study addresses challenges in dental and orthopedic implantology by evaluating the microstructure, mechanical properties, and biological behavior of bilayer coatings composed of a zirconium (Zr) sublayer and an HA top layer, applied via MPS onto titanium alloy. Surface roughness, porosity, and adhesion were characterized, and pull-off and shear tests were used to assess mechanical performance. In vitro biocompatibility was tested using rat mesenchymal stem cells (MSCs) to model osteointegration. The results showed that the MPS-fabricated Zr–HA bilayer coatings achieved a pull-off strength of 28.0 ± 4.2 MPa and a shear strength of 32.3 ± 3.2 MPa, exceeding standard requirements. Biologically, the HA top layer promoted a 45% increase in MSC proliferation over three days compared to the uncoated titanium substrate. Antibacterial testing also revealed suppression of E. coli growth after 14 h. These findings support the potential of MPS-applied Zr-HA coatings to enhance both the mechanical integrity and biological performance of titanium-based orthopedic implants.

The article presents new results of studying the causes of material loss during microplasma spraying (MPS) and substantiates the choice of optimal parameters for efficient spraying of zirconium wire coatings on steel substrates and obtaining coatings with the desired porosity up to 20.3% on a titanium alloy. Optimum spraying parameters provide the maximum material utilization coefficient (MUC) - up to 95%, and the minimum material losses when spraying coatings on small parts: 47% when spraying onto a substrate with an average cross-sectional area of ​​2 mm and less than 1% when spraying onto a substrate with an average diameter of 8 mm. The studies were carried out using a multifactorial experiment with fractional replicas 24-1 with varying such spraying parameters as current strength, spraying distance, plasma-forming gas flow rate, and wire flow rate. To study the distribution of the coating material in the spray spot, macro photography of the metallization figures was carried out and analyzed with the construction of approximating curves. Scanning electron microscopy was used to determine the pore size and porosity of zirconium coatings at different parameters of microplasma spraying on a titanium alloy. Using the methods of regression analysis of the experimental results, equations were obtained that make it possible to assess the degree of influence of the parameters of microplasma spraying on the value of the MUC and the porosity of the coatings, and it was found that the greatest influence is exerted by the current strength and the plasma-forming gas flow rate. The choice of the optimal MPS parameters of a zirconium coating with a porosity suitable for medical implant coatings has been substantiated. В статье представлены новые результаты исследования причин потерь материала в процессе микроплазменного напыления (МПН) и обоснован выбор оптимальных параметров для эффективного напыления циркониевых проволочных покрытий на стальные подложки и получения покрытий с желаемой пористостью до 20,3 % на титановом сплаве. Оптимальные параметры напыления обеспечивают максимальный коэффициент использования материала (КИМ) - до 95%, и минимальные потери материала при напылении покрытий на детали малых размеров: 47% при напылении на подложку со средним диаметром площади поперечного сечения 2 мм и менее 1% при напылении на подложку со средним диаметром 8 мм. Исследования проводились с применением многофакторного эксперимента с дробными репликами 24–1 с варьированием таких параметров напыления, как сила тока, дистанция напыления, расход плазмообразующего газа и скорость подачи проволоки. Для изучения распределения материала покрытия в пятне напыления проводили макросъемку фигур металлизации и анализировали их с построением аппроксимирующих кривых. Методами сканирующей электронной микроскопии определяли размеры пор и пористость циркониевых покрытий при разных параметрах микроплазменного напыления на титановый сплав. Методами регрессионного анализа экспериментальных результатов были получены уравнения, позволяющие оценить степень влияния параметров микроплазменного напыления на величину КИМ и пористость покрытий и установлено, что наибольшее влияние оказывают сила тока и расход плазмообразующего газа. Обоснован выбор оптимальных параметров МПН циркониевого покрытия с пористостью, подходящей для покрытий медицинских имплантатов. Мақалада микроплазмалық тозаңдату (МПТ) кезінде материалды жоғалту себептерін зерттеудің жаңа нәтижелері келтірілген және болат төсеніштерге цирконий сыммен қаптауды тиімді тозаңдату үшін және титан қорытпасында 20,3% дейін қажетті кеуектілігі бар қаптаманы алу үшін оңтайлы параметрлерді таңдау негізделеді. Тозаңдатудың оңтайлы параметрлері материалды пайдаланудың максималды коэффициентін (МПК) - 95%-ға дейін, және шағын көлемдегі бөлшектерге қаптамаларды тозаңдату кезінде материалдың ең аз шығынын қамтамасыз етеді: көлденең қиманың орташа ауданы 2 мм кезінде 47%-ға тең және орташа диаметрі 8 мм төсемдерге тозаңдату кезінде 1%-дан кем болады....

The Paton Welding Journal, 2024, №12. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

The work is devoted to studying the technological capabilities of the processes of microplasma spraying of wires from heat-resistant nickel alloy Inconel 82 with further laser melting of the sprayed layers to produce narrow-path coatings during restoration of worn end faces of ribbed parts, used...