Background

The literature describes ready developed aluminum electroless plating processes which are applied to glass. These processes are based on catalyzing the part to be plated with palladium by a two-step process of dipping the part in a tin chloride solution followed by a palladium chloride solution to render the surface catalytic. Then, the part to be plated is dipped in 1-ethyl 3-methylImidazolium chloride (EMIC or EMIM) - aluminum chloride Room Temperature Ionic Liquid (RTIL) that has Diisobutyl aluminum hydride in toluene as a liquid reducing agent. The main source of aluminium is Al2Cl7- ions.

This process results in small volumes of the prepared RTIL. Therefore, it is very difficult to upscale unless more amounts are prepared. Another problem is the high cost of EMIC or EMIM in addition to its low market availability. This made the process impossible to upscale. The second constraint is that it relies on a two-step catalyzation process that needs to be optimized according to the type of surface that needs to be plated. This made the process hard to optimize for different surfaces.

Summary of Problems:

The extremely high cost of RTILs that limits their up scaling.
The limited availability of RTILs in the market
The difficulty of plating aluminum as an active metal that needs a chemical precursor of an extended electrochemical window in order not to be decomposed during the reduction of aluminum ions.
The inability of electroplating on non-reactive and non-conductive surfaces. The challenge in coating aluminum on extremely small nanoscale objects such as nanoparticles and nanotubes.

Technology Overview

A chemical process that can provide conformal aluminum coats on different substrates which are not necessarily conductive or reactive.

The chemical recipe is based on a Room Temperature Ionic Liquid (RTIL) that is composed of aluminum chloride (AlCl3) and Urea that have a 2:1 molar ratio respectively. Lithium aluminum hydride is used as a reducing agent. The reaction between aluminum chloride and urea results in the production of Al2Cl7- anions which are the main source of aluminum in the reaction. When lithium aluminum hydride decomposes, it donates electrons to deposit aluminum on top of the required surface, providing conformal aluminum coats on different substrates which are not necessarily conductive or reactive.

Benefits

Providing a low cost approach for aluminum electroless plating.
Using cheap market available chemicals.
The developed RTIL has a wide electrochemical window.
The electroless plating electrolyte can plate on non-conductive and non-reactive surfaces.It was proven by experiment the ability of the developed electrolyte to coat aluminum on carbon nanotubes. Therefore, it can be potentially used in coating nanoscale structures with aluminum.

Applications

A chemical process that is proven to be effective in aluminum electroless deposition. It can provide conformal aluminum coats on different substrates which are not necessarily conductive or reactive.

Examples include:

Thin film deposition of aluminum for electronic devices especially temperature sensitive devices, as the coat is done at room temperature.
Aluminum corrosion resistant coats on steel.3- Coating nanoparticles with aluminum to form light weight composites for aerospace, automotive and other structural applications.
Providing an aluminum coat on any surface that can subsequently anodized colored for two beneficial outcomes such as the aesthetic look of the coat as well as the functional value of scratch resistance and corrosion resistance.
Plating aluminum on non-conductive substrates.

Opportunity

Available for exclusive and non-exclusive licensing
Exclusive/non-exclusive evaluation for defined period (set up for options).
Collaborative/supportive research

A Low Cost Ionic Liquid for Aluminum Electroless Deposition

Patents

IP Status

Seeking