The Influence of CrAlN Coating Chemical Composition on Soldering Resistance in Contact with Al-Si-Cu Alloy

Abstract

During the high pressure die casting (HPDC) process the die material is exposed to thermal fatigue, erosion, and corrosion. Corrosion leads to the soldering of cast alloy to tool surfaces which consequently bonds the casting with die material. Besides wear, such a process reduces the casting quality and production efficiency and endangers the tool integrity. Application of thin ceramic coatings on die surfaces reduces the soldering effects and improves the die performance. However, the development of ceramic coatings for these purposes still requires detailed information on the phenomena involved in these processes. In this study, the soldering performance of a complex nanolayer CrAlN coating, with three chemical compositions (high-Cr, balanced Cr:Al, and high-Al content) were evaluated. The cast alloy soldering was evaluated by the detachment test in three configurations. In this test, a simple casting is formed in contact with flat coated surfaces. Upon casting solidification, the formed joint is dismantled, and a force required for this process was recorded. To characterize and quantify the exhibited wear, after the detachment test, surfaces of the coated samples were analyzed by different microscopy techniques. Two forms of wear were detected on investigated samples. Cast alloy soldering processes induced the formation of thin layers of cast alloy on the surfaces of all investigated coatings. Additionally, substrate corrosion through the coating growth defects caused coating layer delamination during the detachment test. The evaluated coatings displayed different behaviors regarding the extent of wear and values of the detachment force. The coating with a balanced CrAlN composition exhibited the best soldering and corrosion resistance and displayed the lowest ejection force. In terms of soldering and corrosion resistance, the high-Al coating outperformed the high-Cr content coating. However, high-Al and high-Cr coating exhibited significantly higher and quite comparable values of detachment force. Based on the quantitative results it was postulated that, besides soldering and substrate corrosion, the casting-coating bonding strength depends also on “pure” sticking effects of cast alloy to coated surfaces.

Temperature Course of the Lead-Free Soldering Profile and the Study of the Influence of Ambient Temperature in its Individual Phases

“…Dlatego zalecane jest stopniowe oraz bardzo powolne nagrzewanie płyty. Podczas dobierania profilu lutowniczego należy uwzględnić takie czynniki jak: wytrzymałość temperaturowa układu w obudowie BGA, temperaturę otoczenia, wielkość i grubość płyty PCB, na której znajduje się układ (odprowadzanie ciepła przez jej powierzchnię), stop spoiwa lutowniczego [11][12][13][14].…”

Mechanical and Tribological Properties of the CrAl/CrAlN and CrAl/CrAlN-(a-CNx) Multilayers Deposited by HIPIMS

“…Investigations regarding metallic/ceramic multilayer coatings deposited from sectioned targets showed the possibility of obtaining a multilayer CrAl/CrAlN deposited from a Cr: 0.25 and Al: 0.75 area ratio by the magnetron co-sputtering pulsed dc method, as well as its characterization by XRD, XPS, and Raman spectroscopy [9]. Other studies of CrAlN coatings deposited by unbalanced magnetron sputtering and different Cr and Al concentrations from sectioned targets demonstrated a good corrosion resistance and adhesion to substrate when Cr and Al content was increased [20]. However, to our knowledge, there are no published studies of CrAl/CrAlN coatings deposited by HIPIMS on AISI-A11 tool steel of sectioned targets and their mechanical and tribological properties.…”

Microstructural, Mechanical and Oxidation Resistance of Nanolayer Sputter-Deposited CrAlN Hard Coatings

“…In this study, we consider the influence of the defects on the oxidation resistance of the nanolayer (Cr,Al)N coating composed of CrAlN/CrN/CrAlN/AlN nanolayers. This coating was used in our previously published study [31], where we investigated the soldering resistance of such nanolayer hard coatings in contact with molten Al-Si-Cu cast alloy at a temperature of 750 • C. We found that this particular coating reduced the soldering of cast alloy to a steel die applied for high-pressure die casting.…”