labelBorderColor: String

Sets the axisX Label border color. Values of labelBorderColor can be “HTML Color Name”, “hex code”, or “rgba values”.

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
 axisX:{
      labelBorderColor: "#FF9A31",
      labelBorderThickness: 1
 },
 .
 . 
});
chart.render();