Conventional means of producing material via metal casting have long been used for centuries. In spite of its advantages in producing durable parts with lower cost implications and the accommodation of large part production, this conventional approach is still characterized by the challenges of high lead time in patterns production, poor surface finish, and the need for secondary manufacturing operations, which always leads to material loss. Hence, the introduction of additive manufacturing (AM) to metal casting process has been immensely recognized because of its huge advantages in negating some of the challenges encountered in the conventional route. However, the inconsistency in the material properties (such as density, strength, elastic modulus, dimensional accuracies, surface finish), produced by one of the AM techniques (rapid sand casting), has not been yielding optimum results to be applied in high-tech application like aerospace and automotive industries. Furthermore, this technique lacks efficient qualification and certification, which contributes to their disadvantages. This review focuses on the challenges and recent progress in producing parts from rapid sand moulds and cores via binder jetting (BJ), as well as the need to incorporate efficient qualification and certification in the future production of parts from rapid sand casting.

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The latest technological requirement demands a huge (but sometimes challenging) variety of properties which perhaps are impossible in monolithic or traditional materials. This has innovated the introduction of reinforcement in traditional materials such that the resulting composite material would be an advantage for the collaborating influence of the combined matrix and the reinforcement. Single-phase ceramics have been limited in application due to low densification and poor properties. Hence, ceramic matrix composite is the family of materials that have undertaken quick innovation in past years because of its auspicious properties for structural and functional usage. This concept has made the incorporation of sintering additives into the monolithic form of ZrO 2 of high importance because of the poor densification and fracture toughness of undoped ZrO 2 . The addition of sintering additives provides good functionality to the improvement of ceramic materials. This paper painstakingly reviews the effects of diverse sintering additives such as carbides, borides, nitrides on the microstructure, densification, and mechanical properties of ZrO 2 ceramic matrix using different sintering techniques and it lastly stated a futuristic approach to the enhancement and characterisation needed for ZrO 2 ceramic matrix composites.

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Monolithic TiB 2 are known to have a good combination of densi cation and hardness which are sometimes useful but limited in application. However, their usage in service at elevated temperatures such as in power thermal plants, cutting tools, tribological purposes (cutting tools, mechanical seals, blast nozzles, and wheel dressing tools), etc leads to catastrophic failure. Hence, the introduction of sintering additives in the TiB 2 matrix has a high in uence on the improvement of its sinterability, and properties (fracture toughness, wear resistance etc.,) of the resulting composite needed to meets the requirement for various industrial applications. In this study, the in uence of SiC as sintering additives on the microstructure, densi cation, hardness and wear performance of TiB 2 ceramic was observed. Hence, TiB 2, TiB 2 -10wt%SiC and TiB 2 -20wt%SiC were sintered at 1850 o C for 10 minutes under 50 MPa. The impacts of SiC on the TiB 2 were observed to improve the microstructure correspondingly improving densi cation and mechanical properties, most especially with the composites with 20wt% SiC. Combined excellent densi cation, hardness and fracture toughness of 99.5%, 25.5 GPa, 4.5 MPa.m 1/2 were achieved respectively for TiB 2 -20wt%SiC. Diverse in-situ phase and microstructural alterations were detected in the sintered composites, and it was discovered that the in-situ phase of TiC serves as the contributing factor to the enhanced features of the composites. Moreover, the coe cient of friction and wear performance outcomes of the synthesized composites described a decrease in the coe cient with an enhanced wear resistance via the increasing SiC particulate, although the application of the load from 10 N-20 N increased the wear rates.